A compressor , comprising: a shell having an enclosed inner space, wherein the shell is formed to have a larger cross-sectional area as it goes from an upper central portion (A11, 111b1) or a bottom central portion (A13, 112b1) to a side central portion (A12, 111b2), wherein curved edge portions of the outer circumferential surface of the shell are formed between the upper central portion (A11, 111b1) and the side central portion (A12, 111b2) of the shell or between the bottom central portion (A13, 112b1) and the side central portion (A12, 111b2) of the shell , an electric motor unit provided in the inner space of the shell to generate a driving force; and a compression unit provided in the inner space of the shell to compress refrigerant while reciprocating a piston in a cylinder by a driving force transmitted from the electric motor unit , wherein a plurality of heat radiation fins is formed on the curved edge portions of the outer circumferential surface of the shell to emit heat generated inside the shell to an outside of the shell , wherein each of the plurality of heat radiation fins includes a curved portion extended from the outer circumferential surface of the shell , a horizontal portion extended in a direction perpendicular to an axial direction from an upper end of the curved portion and a vertical portion extended in the axial direction from a lower end of the curved portion to connect the horizontal portion , and wherein a height of the horizontal portion of the heat radiation fins is lower than or equal to the upper central portion (A11, 111b1) of the shell in the axial direction, and wherein a height of the vertical portion of the heat radiation fins is lower than or equal to the side central portion (A12, 111b2) in a radial direction. a shell having an enclosed inner space, wherein the shell is formed to have a larger cross-sectional area as it goes from an upper central portion (A11, 111b1) or a bottom central portion (A13, 112b1) to a side central portion (A12, 111b2), wherein curved edge portions of the outer circumferential surface of the shell are formed between the upper central portion (A11, 111b1) and the side central portion (A12, 111b2) of the shell or between the bottom central portion (A13, 112b1) and the side central portion (A12, 111b2) of the shell , an electric motor unit provided in the inner space of the shell to generate a driving force; and a compression unit provided in the inner space of the shell to compress refrigerant while reciprocating a piston in a cylinder by a driving force transmitted from the electric motor unit , wherein a plurality of heat radiation fins is formed on the curved edge portions of the outer circumferential surface of the shell to emit heat generated inside the shell to an outside of the shell , wherein each of the plurality of heat radiation fins includes a curved portion extended from the outer circumferential surface of the shell , a horizontal portion extended in a direction perpendicular to an axial direction from an upper end of the curved portion and a vertical portion extended in the axial direction from a lower end of the curved portion to connect the horizontal portion , and wherein a height of the horizontal portion of the heat radiation fins is lower than or equal to the upper central portion (A11, 111b1) of the shell in the axial direction, and wherein a height of the vertical portion of the heat radiation fins is lower than or equal to the side central portion (A12, 111b2) in a radial direction. <EOS>