diff --git a/jsk_naoqi_robot/naoqieus/naoqi-interface.l b/jsk_naoqi_robot/naoqieus/naoqi-interface.l
index 0d79f568b9..cf5cb57405 100644
--- a/jsk_naoqi_robot/naoqieus/naoqi-interface.l
+++ b/jsk_naoqi_robot/naoqieus/naoqi-interface.l
@@ -254,10 +254,11 @@
        (setq wait t))
      ;; set volume and language
      (when volume
-       (send self :set-master-volume (round (* volume 100))))
+       (unless (send self :set-master-volume (round (* volume 100)))
+         (error "Invalid volume argument")))
      (when lang
        (unless (send self :set-language lang)
-         (ros::ros-error ":speak :lang ~A must be English or Japanese" lang)))
+         (error "Invalid language argument")))
      ;; send speech request
      (send speech_msg :data str)
      (ros::publish (format nil "~A/speech" group-namespace) speech_msg)
@@ -345,10 +346,15 @@
   (:set-master-volume
    (volume)
    (let ((ret (instance nao_interaction_msgs::SetAudioMasterVolumeRequest :init)))
-     (ros::wait-for-service (format nil "~A/naoqi_driver/set_volume" group-namespace))
-     (send ret :master_volume :data volume)
-     (ros::service-call (format nil "~A/naoqi_driver/set_volume" group-namespace) ret)
-     ))
+     (if (<= 0 volume 100)
+	 (progn
+	   (ros::wait-for-service (format nil "~A/naoqi_driver/set_volume" group-namespace))
+	   (send ret :master_volume :data volume)
+	   (ros::service-call (format nil "~A/naoqi_driver/set_volume" group-namespace) ret)
+	   t)
+	 (progn
+	   (ros::ros-error ":set-master-volume ~A must be between 0 and 100." volume)
+	   nil))))
   (:get-master-volume
    ()
    (let ((ret (instance nao_interaction_msgs::GetAudioMasterVolumeRequest :init))
@@ -432,6 +438,8 @@
      (ros::wait-for-service (format nil "~A/naoqi_driver/set_language" group-namespace))
      (send ret :data language)
      (setq res (ros::service-call (format nil "~A/naoqi_driver/set_language" group-namespace) ret))
+     (if (not (send res :success))
+         (ros::ros-error ":speak :lang ~A must be English or Japanese" language))
      (send res :success))
    )
   (:get-language