PURPOSE: To improve compression efficiency by eliminataing stagnation of gas in a recessed part created by bending and deforming along an air intake hole and an air exhaust hole.

CONSTITUTION: Rotation of an electric motor is transmitted to a diaphragm 8 through an eccentric shaft 4 and a connecting rod 6. In air intake space 17 formed in a pump head 10, a rubber valve 11 is fixed by a valve holding body 12 having an air intake hole 19a, and in air exhaust space 18, a rubber valve 11 is fixed by a valve holding body 12a having air exhaust holes 20a and 4Oa. When a pump is operated, air is sucked through air intake holes 19a and 19, and is exhausted through air exhaust holes 20 and 20a, but at this time, gas in a valve recess 11b bent and deformed by the air intake hole 19a and the air exhaust hole 20 is sucked or exhausted through a newly arranged air intake hole 49 and the air exhaust hole 40a without causing stagnation.