Provided is a mobile telephone which can easily be found when called in case the mobile telephone is placed on a desk or a floor. An image display plane of a display (5) is arranged on the front surface of a casing (1) of the mobile telephone. A camera (7) is arranged on the rear surface of the casing (1). The mobile telephone includes: a proximity sensor (8), an acceleration sensor (16), and a control circuit (12). The control circuit (12) has: a means for detecting when the casing (1) is placed on an object according to an output value of the proximity sensor (8) and an output value of the acceleration sensor (16); a means for subjecting an image signal obtained from the camera (7) before detection of that the casing (1) is placed on the object, to a color conversion process which converts a color of each pixel into a complementary color in accordance with a predetermined conversion rule; and a means for outputting a color-converted image signal to the display (5) and displaying the color-converted image on the image display surface of the display (5) when a called state is detected after detection of that the casing (1) is placed on the object.