Portable telephone set

A portable telephone, equipped with an opening/closing cover, which houses an operating part. An operating panel is mounted to a main casing in a manner enabling movement between a position at the front face side and a position at the inner side of the main casing, and a compression spring, which urges this operating panel in the direction of the position at the front face side of the main casing is equipped. When the opening/closing cover is at the closed position, the operating panel is positioned at the position at the inner side of the main casing, and when the opening/closing cover is opened, the operating panel is moved to the position at the front face side by the compression spring so that it is positioned at a position at which the operating surface is substantially flush with the back face of the opening/closing cover that is positioned at the opened position. With another aspect of this invention, an opened/closed condition detection sensor is provided, and in response to the opening and closing of the opening/closing cover, an image is displayed on the display panel in accordance with a signal processed image signal.