diff --git a/app/Controllers/Admin/PasswordChange.php b/app/Controllers/Admin/PasswordChange.php
index fee33aa..8b55218 100644
--- a/app/Controllers/Admin/PasswordChange.php
+++ b/app/Controllers/Admin/PasswordChange.php
@@ -19,14 +19,15 @@ class PasswordChange extends BaseController
         helper('admin');
         $rules = [
             'current_password'  => 'required',
-            'new_password'      => 'required|min_length[4]|max_length[255]',
+            'new_password'      => ['required', 'min_length[8]', 'max_length[255]', 'regex_match[/^(?=.*[A-Za-z])(?=.*\d)(?=.*[\W_]).+$/]'],
             'new_password_confirm' => 'required|matches[new_password]',
         ];
         $messages = [
             'current_password'  => ['required' => '현재 비밀번호를 입력해 주세요.'],
             'new_password'      => [
-                'required'   => '새 비밀번호를 입력해 주세요.',
-                'min_length' => '비밀번호는 4자 이상이어야 합니다.',
+                'required'    => '새 비밀번호를 입력해 주세요.',
+                'min_length'  => '비밀번호는 8자 이상이어야 합니다.',
+                'regex_match' => '비밀번호는 영문·숫자·특수문자를 모두 포함해야 합니다.',
             ],
             'new_password_confirm' => [
                 'required' => '비밀번호 확인을 입력해 주세요.',
diff --git a/app/Controllers/Admin/User.php b/app/Controllers/Admin/User.php
index 3e5e450..cb9a502 100644
--- a/app/Controllers/Admin/User.php
+++ b/app/Controllers/Admin/User.php
@@ -83,13 +83,13 @@ class User extends BaseController
     {
         $rules = [
             'mb_id'     => 'required|min_length[2]|max_length[50]|is_unique[member.mb_id]',
-            'mb_passwd' => 'required|min_length[4]|max_length[255]',
+            'mb_passwd' => ['required', 'min_length[8]', 'max_length[255]', 'regex_match[/^(?=.*[A-Za-z])(?=.*\d)(?=.*[\W_]).+$/]'],
             'mb_name'   => 'required|max_length[50]',
             'mb_email'  => 'permit_empty|valid_email|max_length[100]',
             'mb_phone'  => 'permit_empty|max_length[20]',
             'mb_level'  => 'required',
         ];
-        if (! $this->validate($rules)) {
+        if (! $this->validate($rules, ['mb_passwd' => ['min_length' => '비밀번호는 8자 이상이어야 합니다.', 'regex_match' => '비밀번호는 영문·숫자·특수문자를 모두 포함해야 합니다.']])) {
             return redirect()->back()->withInput()->with('errors', $this->validator->getErrors());
         }
         $allowedLevels = array_keys($this->getAssignableLevels());
@@ -154,9 +154,9 @@ class User extends BaseController
         ];
         $passwd = $this->request->getPost('mb_passwd');
         if ($passwd !== '') {
-            $rules['mb_passwd'] = 'min_length[4]|max_length[255]';
+            $rules['mb_passwd'] = ['min_length[8]', 'max_length[255]', 'regex_match[/^(?=.*[A-Za-z])(?=.*\d)(?=.*[\W_]).+$/]'];
         }
-        if (! $this->validate($rules)) {
+        if (! $this->validate($rules, ['mb_passwd' => ['min_length' => '비밀번호는 8자 이상이어야 합니다.', 'regex_match' => '비밀번호는 영문·숫자·특수문자를 모두 포함해야 합니다.']])) {
             return redirect()->back()->withInput()->with('errors', $this->validator->getErrors());
         }
         $allowedLevels = array_keys($this->getAssignableLevels());
diff --git a/app/Controllers/Auth.php b/app/Controllers/Auth.php
index 6d24ba1..d34aa3e 100644
--- a/app/Controllers/Auth.php
+++ b/app/Controllers/Auth.php
@@ -357,7 +357,7 @@ class Auth extends BaseController
     {
         $rules = [
             'mb_id'            => 'required|min_length[4]|max_length[50]|is_unique[member.mb_id]',
-            'mb_passwd'        => 'required|min_length[4]|max_length[255]',
+            'mb_passwd'        => ['required', 'min_length[8]', 'max_length[255]', 'regex_match[/^(?=.*[A-Za-z])(?=.*\d)(?=.*[\W_]).+$/]'],
             'mb_passwd_confirm' => 'required|matches[mb_passwd]',
             'mb_name'          => 'required|max_length[100]',
             'mb_email'         => 'permit_empty|valid_email|max_length[100]',
@@ -374,9 +374,10 @@ class Auth extends BaseController
                 'is_unique'   => '이미 사용 중인 아이디입니다.',
             ],
             'mb_passwd' => [
-                'required'   => '비밀번호를 입력해 주세요.',
-                'min_length'  => '비밀번호는 4자 이상이어야 합니다.',
+                'required'    => '비밀번호를 입력해 주세요.',
+                'min_length'  => '비밀번호는 8자 이상이어야 합니다.',
                 'max_length'  => '비밀번호는 255자 이하여야 합니다.',
+                'regex_match' => '비밀번호는 영문·숫자·특수문자를 모두 포함해야 합니다.',
             ],
             'mb_passwd_confirm' => [
                 'required'  => '비밀번호 확인을 입력해 주세요.',
diff --git a/app/Views/admin/password_change/index.php b/app/Views/admin/password_change/index.php
index 9966717..654d34f 100644
--- a/app/Views/admin/password_change/index.php
+++ b/app/Views/admin/password_change/index.php
@@ -13,6 +13,7 @@
     <div class="flex flex-wrap items-center gap-2">
       <label class="block text-sm font-bold text-gray-700 w-32">새 비밀번호 <span class="text-red-500">*</span></label>
       <input class="border border-gray-300 rounded px-3 py-1.5 text-sm w-60" name="new_password" type="password" required autocomplete="new-password"/>
+      <p class="w-full text-xs text-gray-500 pl-32">8자 이상, 영문·숫자·특수문자를 모두 포함해야 합니다.</p>
     </div>
 
     <div class="flex flex-wrap items-center gap-2">
diff --git a/app/Views/admin/user/create.php b/app/Views/admin/user/create.php
index 50e4447..d0db6e1 100644
--- a/app/Views/admin/user/create.php
+++ b/app/Views/admin/user/create.php
@@ -11,6 +11,7 @@
     <div class="flex flex-wrap items-center gap-2">
       <label class="block text-sm font-bold text-gray-700 w-20">비밀번호 <span class="text-red-500">*</span></label>
       <input class="border border-gray-300 rounded px-3 py-1.5 text-sm w-48" id="mb_passwd" name="mb_passwd" type="password" required/>
+      <p class="w-full text-xs text-gray-500 pl-20">8자 이상, 영문·숫자·특수문자를 모두 포함해야 합니다.</p>
     </div>
     <div class="flex flex-wrap items-center gap-2">
       <label class="block text-sm font-bold text-gray-700 w-20">이름 <span class="text-red-500">*</span></label>
diff --git a/app/Views/admin/user/edit.php b/app/Views/admin/user/edit.php
index 1b7df0b..fbb46bd 100644
--- a/app/Views/admin/user/edit.php
+++ b/app/Views/admin/user/edit.php
@@ -24,6 +24,7 @@ $editLoginLocked = $editLockUntil !== null && $editLockUntil !== '' && strtotime
     <div class="flex flex-wrap items-center gap-2">
       <label class="block text-sm font-bold text-gray-700 w-20">비밀번호</label>
       <input class="border border-gray-300 rounded px-3 py-1.5 text-sm w-48" id="mb_passwd" name="mb_passwd" type="password" placeholder="변경 시에만 입력"/>
+      <p class="w-full text-xs text-gray-500 pl-20">변경 시 8자 이상, 영문·숫자·특수문자를 모두 포함해야 합니다.</p>
     </div>
     <div class="flex flex-wrap items-center gap-2">
       <label class="block text-sm font-bold text-gray-700 w-20">이름 <span class="text-red-500">*</span></label>
diff --git a/app/Views/auth/register.php b/app/Views/auth/register.php
index 7c6ca94..6f993c6 100644
--- a/app/Views/auth/register.php
+++ b/app/Views/auth/register.php
@@ -13,6 +13,7 @@
   <div>
     <label class="block text-sm font-bold text-gray-700 mb-1" for="mb_passwd">비밀번호 <span class="text-red-500">*</span></label>
     <input class="<?= $inputCls ?>" id="mb_passwd" name="mb_passwd" type="password" autocomplete="new-password"/>
+    <p class="mt-1 text-xs text-gray-500">8자 이상, 영문·숫자·특수문자를 모두 포함해야 합니다.</p>
   </div>
   <div>
     <label class="block text-sm font-bold text-gray-700 mb-1" for="mb_passwd_confirm">비밀번호 확인 <span class="text-red-500">*</span></label>