A turbo compressor (100, 200, 300), comprising: a driving unit including a stator and a rotor configured to generate a rotational force and a rotary shaft that is connected to and rotated by the rotor; an impeller connected to the rotary shaft to pressurize a suction refrigerant in the radial direction of the rotary shaft; and a casing configured to receive the driving unit and the impeller and support the rotary shaft, wherein the casing comprises: a first shell having an inner surface to which the stator is fixed, the first shell rotatably supporting the rotary shaft; and a second shell spaced apart from the first shell to surround the first shell and a shell passage for the refrigerant pressurized by the impeller being defined in a space between the first and second shells, wherein the second shell comprises a suction port formed in a position facing a front surface of the impeller and through which the refrigerant can be sucked; characterized in that the second shell further comprises: a discharge port formed through an outer peripheral surface of the second shell to discharge the refrigerant passing through the shell passage; and a sub-frame part (146, 246) to support the rotary shaft in the axial direction and the radial direction, wherein the discharge port is located axially between the impeller and the sub-frame part (146, 246). a driving unit including a stator and a rotor configured to generate a rotational force and a rotary shaft that is connected to and rotated by the rotor; an impeller connected to the rotary shaft to pressurize a suction refrigerant in the radial direction of the rotary shaft; and a casing configured to receive the driving unit and the impeller and support the rotary shaft, wherein the casing comprises: a first shell having an inner surface to which the stator is fixed, the first shell rotatably supporting the rotary shaft; and a second shell spaced apart from the first shell to surround the first shell and a shell passage for the refrigerant pressurized by the impeller being defined in a space between the first and second shells, wherein the second shell comprises a suction port formed in a position facing a front surface of the impeller and through which the refrigerant can be sucked; characterized in that the second shell further comprises: a discharge port formed through an outer peripheral surface of the second shell to discharge the refrigerant passing through the shell passage; and a sub-frame part (146, 246) to support the rotary shaft in the axial direction and the radial direction, wherein the discharge port is located axially between the impeller and the sub-frame part (146, 246). a first shell having an inner surface to which the stator is fixed, the first shell rotatably supporting the rotary shaft; and a second shell spaced apart from the first shell to surround the first shell and a shell passage for the refrigerant pressurized by the impeller being defined in a space between the first and second shells, wherein the second shell comprises a suction port formed in a position facing a front surface of the impeller and through which the refrigerant can be sucked; characterized in that the second shell further comprises: a discharge port formed through an outer peripheral surface of the second shell to discharge the refrigerant passing through the shell passage; and a sub-frame part (146, 246) to support the rotary shaft in the axial direction and the radial direction, wherein the discharge port is located axially between the impeller and the sub-frame part (146, 246). a discharge port formed through an outer peripheral surface of the second shell to discharge the refrigerant passing through the shell passage; and a sub-frame part (146, 246) to support the rotary shaft in the axial direction and the radial direction, wherein the discharge port is located axially between the impeller and the sub-frame part (146, 246).