To provide an air pump increasing a suction/exhaust flow rate of gas and capable of realizing miniaturizing.

The air pump is provided with a pump case 1; diaphragms 21, 22 for partitioning the inside of this pump case 11 to pump chambers 12, 13 and a crank chamber 14; a crank shaft 30 mounted to an output shaft 15a of a driving motor 15 and arranged in the crank chamber 14; connection members 21, 22 of which one end is turnably mounted to the crank shaft 30 and the other end is connected to the diaphragms 21, 22; a suction valve 19a for only permitting flowing-in of air to the pump chambers 12, 13; and an exhaust valve for only permitting flowing out of the air from the pump chambers 12, 13. The first pump chamber 12 and the second pump chamber 13 are arranged at a periphery of the crank chamber 14 by arranging the first diaphragm 21 and the second diaphragm 22 in the pump case 11.