An interface unit 4 for a game machine 1 includes a monitor 10 having a single display surface 10a, and an input module 11 serving as an input device overlaid on the display surface 10a, wherein a plurality of push button panels 16, each of which has a panel main body with enough transparency to allow a screen image on the display surface 10a to be visually seen, partitions the unit 4 into input display parts 4a, which are arranged on partial regions of the display surface 10a in a push-down operable manner, and a multi purpose display part 4b for displaying a screen image with a different purpose from that of the input display parts 4a.