diff --git a/mobile/skin/member/basic/register_form.skin.php b/mobile/skin/member/basic/register_form.skin.php
index 89bb047c6..a8aacd3e0 100644
--- a/mobile/skin/member/basic/register_form.skin.php
+++ b/mobile/skin/member/basic/register_form.skin.php
@@ -125,7 +125,7 @@ add_stylesheet('<link rel="stylesheet" href="'.$member_skin_url.'/style.css">',
 	        <?php if ($config['cf_use_tel']) { ?>
 	        <li>
 	            <label for="reg_mb_tel" class="sound_only">전화번호<?php if ($config['cf_req_tel']) { ?><strong>필수</strong><?php } ?></label>
-	            <input type="text" name="mb_tel" value="<?php echo get_text($member['mb_tel']) ?>" id="reg_mb_tel" class="frm_input full_input <?php echo $config['cf_req_tel']?"required":""; ?>" maxlength="20" <?php echo $config['cf_req_tel']?"required":""; ?> placeholder="전화번호">
+	            <input type="text" name="mb_tel" value="<?php echo get_text($member['mb_tel']) ?>" id="reg_mb_tel" class="frm_input full_input <?php echo $config['cf_req_tel']?"required":""; ?>" <?php if ($config['cf_cert_use'] && ($config['cf_cert_hp'] || $config['cf_cert_sa']) && $member['mb_certify']) { echo "readonly"; } ?> maxlength="20" <?php echo $config['cf_req_tel']?"required":""; ?> placeholder="전화번호">
 	        </li>
 	        <?php } ?>
 	
diff --git a/skin/member/basic/register_form.skin.php b/skin/member/basic/register_form.skin.php
index 0e88ef36b..3b56e5726 100644
--- a/skin/member/basic/register_form.skin.php
+++ b/skin/member/basic/register_form.skin.php
@@ -141,7 +141,7 @@ add_stylesheet('<link rel="stylesheet" href="'.$member_skin_url.'/style.css">',
 	            <?php if ($config['cf_use_hp'] || ($config["cf_cert_use"] && ($config['cf_cert_hp'] || $config['cf_cert_sa']))) {  ?>
 	                <label for="reg_mb_hp">휴대폰번호<?php if ($config['cf_req_hp']) { ?><strong class="sound_only">필수</strong><?php } ?></label>
 	                
-	                <input type="text" name="mb_hp" value="<?php echo get_text($member['mb_hp']) ?>" id="reg_mb_hp" <?php echo ($config['cf_req_hp'])?"required":""; ?> class="frm_input full_input <?php echo ($config['cf_req_hp'])?"required":""; ?>" maxlength="20" placeholder="휴대폰번호">
+	                <input type="text" name="mb_hp" value="<?php echo get_text($member['mb_hp']) ?>" id="reg_mb_hp" <?php echo ($config['cf_req_hp'])?"required":""; ?> class="frm_input full_input <?php echo ($config['cf_req_hp'])?"required":""; ?>" <?php if ($config['cf_cert_use'] && ($config['cf_cert_hp'] || $config['cf_cert_sa']) && $member['mb_certify']) { echo "readonly"; } ?> maxlength="20" placeholder="휴대폰번호">
 	                <?php if ($config['cf_cert_use'] && ($config['cf_cert_hp'] || $config['cf_cert_sa'])) { ?>
 	                <input type="hidden" name="old_mb_hp" value="<?php echo get_text($member['mb_hp']) ?>">
 	                <?php } ?>
diff --git a/theme/basic/mobile/skin/member/basic/register_form.skin.php b/theme/basic/mobile/skin/member/basic/register_form.skin.php
index d59723c90..c3afb973e 100644
--- a/theme/basic/mobile/skin/member/basic/register_form.skin.php
+++ b/theme/basic/mobile/skin/member/basic/register_form.skin.php
@@ -132,7 +132,7 @@ add_stylesheet('<link rel="stylesheet" href="'.$member_skin_url.'/style.css">',
 	        <li>
 	            <label for="reg_mb_hp" class="sound_only">휴대폰번호<?php if ($config['cf_req_hp']) { ?><strong>필수</strong><?php } ?></label>
 	            
-	            <input type="text" name="mb_hp" value="<?php echo get_text($member['mb_hp']) ?>" id="reg_mb_hp" <?php echo ($config['cf_req_hp'])?"required":""; ?> class="frm_input full_input <?php echo ($config['cf_req_hp'])?"required":""; ?>" maxlength="20" placeholder="휴대폰번호">
+	            <input type="text" name="mb_hp" value="<?php echo get_text($member['mb_hp']) ?>" id="reg_mb_hp" <?php echo ($config['cf_req_hp'])?"required":""; ?> class="frm_input full_input <?php echo ($config['cf_req_hp'])?"required":""; ?>" <?php if ($config['cf_cert_use'] && ($config['cf_cert_hp'] || $config['cf_cert_sa']) && $member['mb_certify']) { echo "readonly"; } ?> maxlength="20" placeholder="휴대폰번호">
 	            <?php if ($config['cf_cert_use'] && ($config['cf_cert_hp'] || $config['cf_cert_sa'])) { ?>
 	            <input type="hidden" name="old_mb_hp" value="<?php echo get_text($member['mb_hp']) ?>">
 	            <?php } ?>
diff --git a/theme/basic/skin/member/basic/register_form.skin.php b/theme/basic/skin/member/basic/register_form.skin.php
index 0e88ef36b..3b56e5726 100644
--- a/theme/basic/skin/member/basic/register_form.skin.php
+++ b/theme/basic/skin/member/basic/register_form.skin.php
@@ -141,7 +141,7 @@ add_stylesheet('<link rel="stylesheet" href="'.$member_skin_url.'/style.css">',
 	            <?php if ($config['cf_use_hp'] || ($config["cf_cert_use"] && ($config['cf_cert_hp'] || $config['cf_cert_sa']))) {  ?>
 	                <label for="reg_mb_hp">휴대폰번호<?php if ($config['cf_req_hp']) { ?><strong class="sound_only">필수</strong><?php } ?></label>
 	                
-	                <input type="text" name="mb_hp" value="<?php echo get_text($member['mb_hp']) ?>" id="reg_mb_hp" <?php echo ($config['cf_req_hp'])?"required":""; ?> class="frm_input full_input <?php echo ($config['cf_req_hp'])?"required":""; ?>" maxlength="20" placeholder="휴대폰번호">
+	                <input type="text" name="mb_hp" value="<?php echo get_text($member['mb_hp']) ?>" id="reg_mb_hp" <?php echo ($config['cf_req_hp'])?"required":""; ?> class="frm_input full_input <?php echo ($config['cf_req_hp'])?"required":""; ?>" <?php if ($config['cf_cert_use'] && ($config['cf_cert_hp'] || $config['cf_cert_sa']) && $member['mb_certify']) { echo "readonly"; } ?> maxlength="20" placeholder="휴대폰번호">
 	                <?php if ($config['cf_cert_use'] && ($config['cf_cert_hp'] || $config['cf_cert_sa'])) { ?>
 	                <input type="hidden" name="old_mb_hp" value="<?php echo get_text($member['mb_hp']) ?>">
 	                <?php } ?>