Provided is an excellent robot device capable of preferably detecting difference between dirt and a scratch on a lens of a camera and difference between dirt and a scratch on a hand. A robot device detects a site in which there is the dirt or the scratch using an image of the hand taken by a camera as a reference image. Further, this determines whether the detected dirt or scratch is due to the lens of the camera or the hand by moving the hand. The robot device performs cleaning work assuming that the dirt is detected, and then this detects the difference between the dirt and the scratch depending on whether the dirt is removed.