To enable the degree of erection to be controlled and the bottom of a penis, which erects according to the degree of erection to be bound appropriately.

A cylinder 40 is detachably mounted on an outer cylinder 11a of a decompression cylinder. The decompression cylinder is sealed by inserting a penis P into a ring body 55 mounted on the opening 19 of an inner cylinder 11b and then continuing to press a body. If a piston 42 descends in the cylinder 40 by operating a lever 45, air in a first air chamber R1 moves to a second air chamber R2 through an air release valve 49. If the piston 42 ascends again, the inside of the first air chamber R1 is decompressed. Thereby, the penis P is congested and erects. On the other hand, air in the second air chamber R2 is supplied to the ring body 55 from a hose 31 through a nozzle 32, and the penis is bound, so that the state of erection is kept.