A scroll compressor, comprising: a casing (110, 210) having a hermetic inner space divided into a low pressure portion (111, 211) and a high pressure portion; an orbiting scroll disposed within the inner space of the casing (110, 210) and performing an orbiting motion; a non-orbiting scroll (150, 250) forming a compression chamber together with the orbiting scroll, the compression chamber having a suction chamber, an intermediate pressure chamber and a discharge chamber; a back pressure chamber assembly (160, 260) coupled to the non-orbiting scroll (150, 250) to form a back pressure chamber (160a, 260a); a communication passage formed through the intermediate pressure chamber and bypassing a refrigerant of the intermediate pressure chamber to the low pressure portion of the casing; a first valve assembly (170, 255) opening and closing the communication passage; and a second valve assembly (180, 280) provided outside the casing and connected to the first valve assembly (170, 255) by a connection pipe penetrating through the casing (110, 210), the second valve assembly (180, 280) controlling an opening/closing operation of the first valve assembly (170, 255) such that the first valve assembly (170, 255) opens and closes the communication passage, characterized in that the communication passage comprises a bypass hole (151b, 251b) formed through the non-orbiting scroll (150, 250) and communicating with the intermediate pressure chamber, and wherein a check valve (155, 255) for opening and closing the bypass hole (151b, 251b) according to pressure of the intermediate pressure chamber is provided on the bypass hole (151b, 251b) at outside of the intermediate pressure chamber. a casing (110, 210) having a hermetic inner space divided into a low pressure portion (111, 211) and a high pressure portion; an orbiting scroll disposed within the inner space of the casing (110, 210) and performing an orbiting motion; a non-orbiting scroll (150, 250) forming a compression chamber together with the orbiting scroll, the compression chamber having a suction chamber, an intermediate pressure chamber and a discharge chamber; a back pressure chamber assembly (160, 260) coupled to the non-orbiting scroll (150, 250) to form a back pressure chamber (160a, 260a); a communication passage formed through the intermediate pressure chamber and bypassing a refrigerant of the intermediate pressure chamber to the low pressure portion of the casing; a first valve assembly (170, 255) opening and closing the communication passage; and a second valve assembly (180, 280) provided outside the casing and connected to the first valve assembly (170, 255) by a connection pipe penetrating through the casing (110, 210), the second valve assembly (180, 280) controlling an opening/closing operation of the first valve assembly (170, 255) such that the first valve assembly (170, 255) opens and closes the communication passage, characterized in that the communication passage comprises a bypass hole (151b, 251b) formed through the non-orbiting scroll (150, 250) and communicating with the intermediate pressure chamber, and wherein a check valve (155, 255) for opening and closing the bypass hole (151b, 251b) according to pressure of the intermediate pressure chamber is provided on the bypass hole (151b, 251b) at outside of the intermediate pressure chamber.