A reciprocating compressor, wherein a flange unit connected to the mover constituting the reciprocating motor is installed on the piston constituting the compressing unit, the distance between the piston flange unit and the front frame of the frame unit is shorter than that of the between the piston flange unit and the reciprocating motor. In the process of being transmitted the linear reciprocal movement driving force of the reciprocating motor and compressing the gas in the compressing unit, the stability of the compressor is raised by preventing the components moving together with the mover of reciprocating motor from impacting with other components by the displacement generated by compression force applying the piston constituting the compressing unit. Also, the size of compressor can be scaled down by compactly constituting the components.