An input display device comprises an operation panel including a first display operation area that enables operation screens to be switched hierarchically based on a selected operation key and to display a fixed-arrangement of operation keys in respective layers, and a second display operation area that displays an operation history indicating that the operation key has been selected; a selected key use determination unit configured to determine which of the operation keys has been selected when the operation key is selected from one of the first display operation area and the second display operation area; a storage processing unit configured to successively store results determined by the selected key use determination unit into a storage device as operation history information; and a selected key use history display control unit configured to display the operation history information stored in the storage device into the second display operation area.