A scroll compressor comprising: a casing having an internal space; a driving unit for rotating a rotary shaft; a first scroll accommodated in the casing and connected to the rotary shaft to make an orbiting movement; a second scroll engaged with the first scroll to form a compression chamber and having a bypass hole for bypassing a refrigerant sucked into the compression chamber to the internal space of the casing; and a back-pressure chamber assembly configured for pressing the second scroll toward the first scroll, wherein the back-pressure chamber assembly includes: a back-pressure space configured to communicate with the compression chamber to accommodate a refrigerant having intermediate pressure; and a first valve unit, having a valve space and a bypass valve movable arranged within the valve space, the first valve unit being configured for allowing the bypass hole and the internal space of the casing to selectively communicate with each other according to operation modes, characterized in that the back-pressure chamber assembly further includes: a second valve unit, fixed to the casing, having an inlet for receiving a refrigerant from the back-pressure space and an outlet for supplying the refrigerant to the first valve unit, the second valve unit being configured to operate the first valve unit by selectively opening/closing the inlet and the outlet; and a leakage passage (155c, 261g) provided to allow the valve space and the internal space of the casing to communicate with each other. a casing having an internal space; a driving unit for rotating a rotary shaft; a first scroll accommodated in the casing and connected to the rotary shaft to make an orbiting movement; a second scroll engaged with the first scroll to form a compression chamber and having a bypass hole for bypassing a refrigerant sucked into the compression chamber to the internal space of the casing; and a back-pressure chamber assembly configured for pressing the second scroll toward the first scroll, wherein the back-pressure chamber assembly includes: a back-pressure space configured to communicate with the compression chamber to accommodate a refrigerant having intermediate pressure; and a first valve unit, having a valve space and a bypass valve movable arranged within the valve space, the first valve unit being configured for allowing the bypass hole and the internal space of the casing to selectively communicate with each other according to operation modes, characterized in that the back-pressure chamber assembly further includes: a second valve unit, fixed to the casing, having an inlet for receiving a refrigerant from the back-pressure space and an outlet for supplying the refrigerant to the first valve unit, the second valve unit being configured to operate the first valve unit by selectively opening/closing the inlet and the outlet; and a leakage passage (155c, 261g) provided to allow the valve space and the internal space of the casing to communicate with each other. a back-pressure space configured to communicate with the compression chamber to accommodate a refrigerant having intermediate pressure; and a first valve unit, having a valve space and a bypass valve movable arranged within the valve space, the first valve unit being configured for allowing the bypass hole and the internal space of the casing to selectively communicate with each other according to operation modes, characterized in that the back-pressure chamber assembly further includes: a second valve unit, fixed to the casing, having an inlet for receiving a refrigerant from the back-pressure space and an outlet for supplying the refrigerant to the first valve unit, the second valve unit being configured to operate the first valve unit by selectively opening/closing the inlet and the outlet; and a leakage passage (155c, 261g) provided to allow the valve space and the internal space of the casing to communicate with each other. a second valve unit, fixed to the casing, having an inlet for receiving a refrigerant from the back-pressure space and an outlet for supplying the refrigerant to the first valve unit, the second valve unit being configured to operate the first valve unit by selectively opening/closing the inlet and the outlet; and a leakage passage (155c, 261g) provided to allow the valve space and the internal space of the casing to communicate with each other.