diff --git a/js/inquiry.form.js b/js/inquiry.form.js
index 13c98e0..b33d424 100644
--- a/js/inquiry.form.js
+++ b/js/inquiry.form.js
@@ -5,6 +5,32 @@ $(function() {
     });
   }
 
+  $("a[minus]").each(function(index, element) {
+    $(element).click(function() {
+      var targetId = $(this).data("target");
+      var $targetInput = $("#" + targetId);
+      var minVal = $targetInput.data("min");
+      var inputVal = parseInt($targetInput.val());
+      if (inputVal > minVal) {
+        inputVal -= 1;
+        $targetInput.val(inputVal);
+      }
+    });
+  });
+
+  $("a[plus]").each(function(index, element) {
+    $(element).click(function() {
+      var targetId = $(this).data("target");
+      var $targetInput = $("#" + targetId);
+      var maxVal = $targetInput.data("max");
+      var inputVal = parseInt($targetInput.val());
+      if (inputVal < maxVal) {
+        inputVal += 1;
+        $targetInput.val(inputVal);
+      }
+    });
+  });
+
   $("#adult_number").combobox({
     maxLength: 3,
     source: [{