Abstract: An improved air pump comprises at least two parallel cylinder chambers communicating via two channels with a receiving space in which an air valve connecting device is disposed for injecting high pressure air into an object to be inflated. A pressure releasing member is disposed between the channels and the receiving space for regulating the pace of pumping the air into the object. When the air pressure inside the object is low, the pumping of the air into the object is done rapidly. When the air pressure inside the object has reached a high level, the pumping of the air into the object is done by only one cylinder chamber of the air pump.