A device inspection apparatus that is capable of judging the functions of operating control buttons on a cellular phone or like device automatically and easily. The device inspection apparatus comprises an adapter unit 2 on which a cellular phone 1 is mounted; a camera 4 for picking up the image of an LCD panel 3, which serves as a display section for the cellular phone 1; a plunger unit 7, which has a plurality of releases 6 for pressing a key button 5 on the cellular phone 1; a computer 8 for controlling the operation of the plunger unit 7 and exercising control; and a monitor 9 for displaying an LCD panel image and an image based on a signal from the computer 8. A still picture, motion picture, or audio output, which is acquired when a release 6 presses a key button 5, is compared against a predetermined expected image or sound to judge the functionality of the cellular phone 1.