A linear compressor comprising: a shell provided with a refrigerant inlet; a cylinder arranged within the shell to provide a compression space; a piston configured for reciprocating within the cylinder to compress a refrigerant in the compression space; and a motor assembly provided with a permanent magnet, being configured for providing a driving force to the piston, wherein the piston comprises: a piston body with a cylindrical outer circumference; and a valve support portion provided at an end of the piston body, the valve support portion having a suction hole through which the refrigerant can flow into the compression space, characterized in that the valve support portion includes a first non-surface-treated portion which is not surface-treated and is made of a nonmagnetic material, wherein the piston body includes: a first outer circumferential surface as a surface-treated portion which is processed with a material having a set hardness value; and a second outer circumferential surface as a second non-surface-treated portion which is not processed and is made of a nonmagnetic material, and wherein the first non-surface-treated portion of the valve support portion is spaced from the second non-surface-treated portion of the piston body. a shell provided with a refrigerant inlet; a cylinder arranged within the shell to provide a compression space; a piston configured for reciprocating within the cylinder to compress a refrigerant in the compression space; and a motor assembly provided with a permanent magnet, being configured for providing a driving force to the piston, wherein the piston comprises: a piston body with a cylindrical outer circumference; and a valve support portion provided at an end of the piston body, the valve support portion having a suction hole through which the refrigerant can flow into the compression space, characterized in that the valve support portion includes a first non-surface-treated portion which is not surface-treated and is made of a nonmagnetic material, wherein the piston body includes: a first outer circumferential surface as a surface-treated portion which is processed with a material having a set hardness value; and a second outer circumferential surface as a second non-surface-treated portion which is not processed and is made of a nonmagnetic material, and wherein the first non-surface-treated portion of the valve support portion is spaced from the second non-surface-treated portion of the piston body. a piston body with a cylindrical outer circumference; and a valve support portion provided at an end of the piston body, the valve support portion having a suction hole through which the refrigerant can flow into the compression space, characterized in that the valve support portion includes a first non-surface-treated portion which is not surface-treated and is made of a nonmagnetic material, wherein the piston body includes: a first outer circumferential surface as a surface-treated portion which is processed with a material having a set hardness value; and a second outer circumferential surface as a second non-surface-treated portion which is not processed and is made of a nonmagnetic material, and a first outer circumferential surface as a surface-treated portion which is processed with a material having a set hardness value; and a second outer circumferential surface as a second non-surface-treated portion which is not processed and is made of a nonmagnetic material, and wherein the first non-surface-treated portion of the valve support portion is spaced from the second non-surface-treated portion of the piston body.