A linear compressor (10) includes a shell (110) provided with a refrigerant inlet (101); a cylinder (120) provided to an inside of the shell to form a compression space; a piston (130) reciprocating inside the cylinder to compress a refrigerant in the compression space; and a motor assembly (200) providing a driving force to the piston and provided with a permanent magnet (230), wherein the piston includes a piston body (131) having a cylindrical outer circumference and a surface-treated portion (310) which is processed with a material having a set hardness value, and a valve support unit (133) forming an end of the piston body and having a suction hole (133b) suctioning the refrigerant into the compression space, the valve support unit (133) forming a first non-surface-treated portion (133a) which is not surface-treated.
