A reciprocating compressor comprises a reciprocating motor (30) disposed in a casing (10), and generating a driving force; a compression unit (40) for sucking, compressing, and discharging gas by the driving force of the reciprocating motor (30); a resonant spring unit (50) for providing a reciprocating movement of the reciprocating motor (30) with a resonant movement; and at least two spring supporting frame (22,23) by which the resonant spring unit (50) is supported, wherein one of the spring supporting frames (22) is inserted into another spring supporting frame (23) for being coupled with each other. Accordingly, since an initial location of the piston (42) can be readily adjusted, a production process is simplified in producing a reciprocating compressor, and thus its productivity can be improved.