Provided is a portable electronic device which can equalize deterioration of a display device and reduce a deterioration speed, even during a time when a user is performing input operation. When the user is continuously using (operating) keys other than call start and call end keys (14a, 14b), it can be estimated that the user is playing a game or editing on the portable telephone. Therefore, deterioration of a display device configuring a display section (30) is equalized and the deterioration speed is reduced by reducing luminance gradation of display of an area not related to the game and editing on the display section (30).