Gas compressor having a check valve

A compressor includes a compression mechanism for suctioning gas through a suction path to compress the gas and discharging the compressed gas and a check valve for preventing backward-flow of the gas in the suction path. The check valve includes an accommodation hole (its one end is opened toward the suction path and its another end is functioned as a reservoir), a valving element accommodated within the accommodation hole movably, a valve seat provided at the opened end of the accommodation hole for closing the suction path while the valving element is pressed thereonto and an urging component for urging the valving element toward the valve seat. A release groove is grooved on an inner surface of the accommodation hole. The reservoir is communicated with the suction path through the release groove. The compressor can reduce machining cost, component count and weight in respect to the check valve.