A linear compressor comprising: a shell including an intake pipe configured to receive a refrigerant therein; a cylinder provided inside the shell; a piston configured to reciprocate in an axial direction inside the cylinder, the piston including a piston body; and an intake muffler (200, 200A, 200B) including a first muffler, wherein the first muffler includes a first muffler body disposed inside the piston body and a first muffler flange extending in a radial direction from the first muffler body; wherein the first muffler body defines a main flow passage having an inlet hole for receiving the refrigerant into the main flow passage; and wherein the linear compressor further comprises: at least one auxiliary flow passage (PA2, PA2-1, PA2-2) disposed between an outer peripheral surface of the first muffler body and an inner peripheral surface of the piston body and fluidly connecting a space between the first muffler body and the piston body to an outside of the piston and/or to an inside of the intake muffler (200, 200A, 200B); characterized in that a cross-sectional area of the auxiliary flow passage (PA2, PA2-1, PA2-2) is less than a cross-sectional area of the inlet hole of the main flow passage, wherein the cross-sectional area of the auxiliary flow passage (PA2, PA2-1, PA2-2) is greater than or equal to 10 % of the cross-sectional area of the inlet hole of the main flow passage. a shell including an intake pipe configured to receive a refrigerant therein; a cylinder provided inside the shell; a piston configured to reciprocate in an axial direction inside the cylinder, the piston including a piston body; and an intake muffler (200, 200A, 200B) including a first muffler, wherein the first muffler includes a first muffler body disposed inside the piston body and a first muffler flange extending in a radial direction from the first muffler body; wherein the first muffler body defines a main flow passage having an inlet hole for receiving the refrigerant into the main flow passage; and wherein the linear compressor further comprises: at least one auxiliary flow passage (PA2, PA2-1, PA2-2) disposed between an outer peripheral surface of the first muffler body and an inner peripheral surface of the piston body and fluidly connecting a space between the first muffler body and the piston body to an outside of the piston and/or to an inside of the intake muffler (200, 200A, 200B); characterized in that a cross-sectional area of the auxiliary flow passage (PA2, PA2-1, PA2-2) is less than a cross-sectional area of the inlet hole of the main flow passage, wherein the cross-sectional area of the auxiliary flow passage (PA2, PA2-1, PA2-2) is greater than or equal to 10 % of the cross-sectional area of the inlet hole of the main flow passage. at least one auxiliary flow passage (PA2, PA2-1, PA2-2) disposed between an outer peripheral surface of the first muffler body and an inner peripheral surface of the piston body and fluidly connecting a space between the first muffler body and the piston body to an outside of the piston and/or to an inside of the intake muffler (200, 200A, 200B); characterized in that a cross-sectional area of the auxiliary flow passage (PA2, PA2-1, PA2-2) is less than a cross-sectional area of the inlet hole of the main flow passage, wherein the cross-sectional area of the auxiliary flow passage (PA2, PA2-1, PA2-2) is greater than or equal to 10 % of the cross-sectional area of the inlet hole of the main flow passage.