A scroll compressor, comprising: a casing; a compression unit provided in an inner space of the casing to form a compression chamber composed of an inner pocket and an outer pocket by a pair of a first scroll and a second scroll; and bypass holes (1511, 1512, 1521, 1522) provided in the compression unit to bypass refrigerant sucked into the compression chamber to the inner space of the casing to vary compression capacity, wherein the bypass holes (1511, 1512, 1521, 1522) are formed in a first compression chamber (Ap) constituting the inner pocket and a second compression chamber (Bp) constituting an outer pocket to be located in compression chambers having different pressures along a movement path of the respective compression chambers, a back pressure chamber assembly provided on a rear surface of the second scroll to form a back pressure chamber so as to pressurize the second scroll toward the first scroll; a first valve assembly provided in the back pressure chamber assembly to selectively open and close the bypass hole according to the operation mode; and a second valve assembly provided at an outside of the casing to operate the first valve assembly, wherein the bypass hole comprises the first bypass hole (1511, 1521) and the second bypass hole (1512, 1522) located at different points along an advancing direction of the compression chamber, wherein the first valve assembly comprises bypass valves operated together by the second valve assembly, wherein the back pressure chamber assembly comprises a plurality of valve spaces each containing a bypass valve for selectively opening and closing the bypass holes (1511, 1512, 1521, 1522) by moving upward and downward in the valve space, and a differential pressure space having a predetermined volume and formed on a side surface of each bypass valve in the valve space, wherein the first bypass hole (1511, 1521) is located within a range of the outermost compression chamber formed at the time point at which the first scroll reaches a compression start angle, and wherein the second bypass hole (1512, 1522) is located within a range of the other compression chamber successively located at the discharge side than the outermost compression chamber at the time point at which the first scroll reaches the compression start angle, characterized in that the second valve assembly is fixed to an outer circumferential surface of the casing, and coupled to a connection portion coupled through the casing to transfer refrigerant to the differential pressure space. a casing; a compression unit provided in an inner space of the casing to form a compression chamber composed of an inner pocket and an outer pocket by a pair of a first scroll and a second scroll; and bypass holes (1511, 1512, 1521, 1522) provided in the compression unit to bypass refrigerant sucked into the compression chamber to the inner space of the casing to vary compression capacity, wherein the bypass holes (1511, 1512, 1521, 1522) are formed in a first compression chamber (Ap) constituting the inner pocket and a second compression chamber (Bp) constituting an outer pocket to be located in compression chambers having different pressures along a movement path of the respective compression chambers, a back pressure chamber assembly provided on a rear surface of the second scroll to form a back pressure chamber so as to pressurize the second scroll toward the first scroll; a first valve assembly provided in the back pressure chamber assembly to selectively open and close the bypass hole according to the operation mode; and a second valve assembly provided at an outside of the casing to operate the first valve assembly, wherein the bypass hole comprises the first bypass hole (1511, 1521) and the second bypass hole (1512, 1522) located at different points along an advancing direction of the compression chamber, wherein the first valve assembly comprises bypass valves operated together by the second valve assembly, wherein the back pressure chamber assembly comprises a plurality of valve spaces each containing a bypass valve for selectively opening and closing the bypass holes (1511, 1512, 1521, 1522) by moving upward and downward in the valve space, and a differential pressure space having a predetermined volume and formed on a side surface of each bypass valve in the valve space, wherein the first bypass hole (1511, 1521) is located within a range of the outermost compression chamber formed at the time point at which the first scroll reaches a compression start angle, and wherein the second bypass hole (1512, 1522) is located within a range of the other compression chamber successively located at the discharge side than the outermost compression chamber at the time point at which the first scroll reaches the compression start angle, characterized in that the second valve assembly is fixed to an outer circumferential surface of the casing, and coupled to a connection portion coupled through the casing to transfer refrigerant to the differential pressure space.