Abstract: A bidirectional axial fan device includes: a moving blade member with a plurality of vanes; and a casing that includes a mounting portion, a frame, and a plurality of spokes, a motor being mounted to the mounting portion, the frame forming a ventilation hole. The plurality of spokes couple the mounting portion to the frame at an exhaust air side during a normal rotation of the motor. An inner peripheral surface of the frame has a multiple stage shape, in which a part on the exhaust air side during the normal rotation has a diameter larger than a diameter of a part on an air intake side during the normal rotation, such that intervals between tops on the exhaust air side during the normal rotation at outer peripheral edges of the plurality of vanes and the inner peripheral surface of the frame are expanded.