PURPOSE: To obtain an air pump device wherein a driving motor or an air cylinder is easily attached and detached.

CONSTITUTION: An air pump device is composed of a driving motor 1, an air cylinder 2 driven by the driving motor 1 for intake and discharge on a running passage of a tape, an installation plate 3, screws 4 and 6 for connecting the driving motor 1 to the air cylinder 2, an eccentric frame 9 journalled eccentrically to a driving shaft 8 of the driving motor 1, a bearing 10 arranged on an outer periphery of the eccentric frame 9, a shaft 20 whose one end is abutted against an outer peripheral end surface of the bearing 10, the other end is abutted against a piston 12 of the air cylinder 2, and a compression coil spring 19 which presses the shaft 20 against the outer peripheral end surface of the bearing 10.