A compressor includes a cylinder comprising a cylinder body which has a cylindrical shape and defining a compression space for refrigerant gas, a piston configured to be reciprocated in an axial direction within the cylinder body and to compress the refrigerant gas in the compression space, and a frame in which the cylinder is received, the frame defining a gas hole, one side of the gas hole communicating with outside so that the refrigerant gas is introduced, the other side of the gas hole extending up to an inner circumferential surface so as to guide the refrigerant gas.