A linear compressor comprises: a fixed member including a cylinder for providing a refrigerant compression space; a movable member, which includes a piston for compressing refrigerant inside the cylinder and a supporter composed of a center portion being aligned with a center of the piston and a support portion extended radially of the piston and which makes a linear reciprocating movement about the fixed member; a plurality of mainsprings supported on the support portion of the supporter, for elastically supporting the piston in an axial direction; and a mass member, which includes a center portion to couple with the center portion of the supporter and a plurality of ends extended from the center portion to maintain an air-gap towards the support portion of the supporter and towards the mainsprings. The linear compressor of the present invention can accommodate a maximum mass member in a defined space of a linearly reciprocating movable member, so material loss is prevented and more installation space can be secured.