To improve heat radiation effect to enhance convenience for use and reduce cost.

A driver 18 is installed on a low temperature tank side of a double-body tank to increase the heat radiation effect. Near a bottom dead center of a high pressure piston 4' of a second stage high pressure cylinder 17, choke action acts and a discharge port for discharging residual pressure air is disposed to smoothen movement the high pressure piston. A bearing case is integral with a filter case 22, and intake air from a filter 14 passes near a bearing to enhance a cooling effect. Therefore, a portable type compressor is compact and structure thereof is simple to reduce the cost, while enhancing convenience for use.