To explain the result of treatment to the present and a method of treatment in the future to a patient while comparing and observing both of the still picture of a state before the treatment and the moving picture of a present state on a display by simultaneously and parallelly displaying both of the pictures on the same display screen so as to compare and display the primary state before the start of the treatment and the present state.

This device comprises: an intraoral photographing camera 10; the display 30 for video-displaying the the image picked up by the camera 10; and a controller (operation panel) 20 having a memory device for storing and retaining the image picked up by the camera 10. The memory device stores and retains the still picture photographed by the camera 10 and the moving picture recorded through a prescribed period, and can simultaneously and parallelly display the stored and retained still picture B, C, D, e.g., and the previously recorded moving pictures or a moving picture A photographed presently on the display 30.