To improve noise eliminating effect of an air pump, and also regulate a noise eliminating mechanism easily by installing a noise eliminating plate in which an opening port which is smaller than a suction port or a discharge port is drilled on the vicinity of a center part.

In respective ports of an air intake port 3 and an air discharging port 4 arranged along the rotational direction of an impeller on the front end surface lower part of a housing 2, flanges 5 are formed, and an air using apparatus and a silencer are fixed by a screw and the like. A noise eliminating plate 6 in which an installing hole is arranged on the same position as the installing screw of the flange 5 is held between silencers, or only noise eliminating plate 6 is installed and fixed on the end part of the flange 5 without installing the silencer. Or the noise eliminating plate 6 is installed on the suction port of a silencer. A plurality of the hole opening ports 7 of the noise eliminating plates 6 are different from each other in respective noise eliminating plates 6, and the maximum sizes of the opening port are prepared from a parts corresponding to the inner diameter of the suction port or the discharging port of the flange 5 within a size of several mm degrees.