To reduce the number of part items and offer simpler and smaller construction for easy assembly on other equipment.

In a pump case 14 internally mounted with a diaphragm 16a forming a pump chamber 15 communicating with a pressure chamber, exhaust valves (a constant speed exhaust valve 12 and a quick exhaust valve 13) are provided for making air escape from the pressure chamber to reduce pressure in the pressure chamber. The pump chamber 15 and the exhaust valves are integrated with each other.