The present invention provides a reciprocating compressor that compresses a gas, including: a piston; a cylinder that includes a hole portion into which the piston is inserted so as to be movable in the axial direction in a reciprocating manner and includes a compression chamber which is formed in an area of the hole portion near a front end of the piston so that a gas is introduced into the compression chamber; a crank mechanism that drives the piston so that the gas introduced into the compression chamber is compressed by the piston; and a piston ring that is fitted to the outside of the piston and slides on an inner surface forming the hole portion of the cylinder, wherein a tapered portion is formed in an end, which is located near a base end of the piston, in the inner surface forming the hole portion of the cylinder.