When a first screen is displayed on a display surface, for a touch operation in which a duration time of a touch on the operation surface is less than a predetermined time, a function corresponding to the touch operation is not performed, and in response to a predetermined touch operation in which the duration time of the touch on the operation surface is at least the predetermined time, a first function corresponding to the predetermined touch operation is performed. When a second screen is displayed on the display surface, a second function is performed in response to a touch operation in which the duration time of the touch on the operation surface is less than the predetermined time.