A compressor, comprising: a case; a fixed scroll fixed to an inside of the case; an orbiting scroll provided to move about the fixed scroll; a compression unit formed by the fixed scroll and the orbiting scroll and configured to have a volume that is reduced while the compression unit moves toward the center of the fixed scroll and the orbiting scroll, according to the movement of the orbiting scroll; a suction unit configured to suction refrigerant to be delivered to the compression unit; a discharge unit to which refrigerant compressed by the compression unit is discharged, wherein the fixed scroll comprises a bypass flow path configured to connect the suction unit to the compression unit, the bypass flow path (100, 200) including a suction unit flow path (110,410) and a compression unit flow path (120,420); a cylinder space (140,240) provided on the bypass flow path (100,200,400), the cylinder space (140,240,440) being connected to the suction unit via the suction unit flow path and being connected to the compression unit via the compression unit flow path; a discharge unit flow path (130,230,430) configured to connect the cylinder space (140,240) to the discharge unit; a valve (150,250,350,450) disposed to be movable back and forth in the cylinder space (140,440) to open and close the bypass flow path according to a difference between a discharge pressure of the discharge unit and a suction pressure of the suction unit, wherein the valve (150,250,350,450) is configured to move in a first direction toward the suction unit flow path (110,410) to cut off the suction unit flow path (110,410) from the compression unit flow path (120,420) to thereby close the bypass flow path (100,200), and to move in a second direction, opposite to the first direction, to connect the suction unit flow path (110,410) and the compression unit flow path (120,420), characterised in that said movement in the second direction is toward the discharge unit flow path (130,230,430) and the valve (150,250,350,450) includes a first side compressed by the suction pressure of the suction unit and a second side compressed by the discharge pressure of the discharge unit, the first and second sides being on opposite sides of the valve (150,250,350,450), wherein the valve (150,250,350,450) further comprises an opening unit on a lateral side of the valve (150, 250, 350, 450) between said first and second sides, and the bypass flow path (100, 200, 400) is opened and closed by said opening unit. a case; a fixed scroll fixed to an inside of the case; an orbiting scroll provided to move about the fixed scroll; a compression unit formed by the fixed scroll and the orbiting scroll and configured to have a volume that is reduced while the compression unit moves toward the center of the fixed scroll and the orbiting scroll, according to the movement of the orbiting scroll; a suction unit configured to suction refrigerant to be delivered to the compression unit; a discharge unit to which refrigerant compressed by the compression unit is discharged, wherein the fixed scroll comprises a bypass flow path configured to connect the suction unit to the compression unit, the bypass flow path (100, 200) including a suction unit flow path (110,410) and a compression unit flow path (120,420); a cylinder space (140,240) provided on the bypass flow path (100,200,400), the cylinder space (140,240,440) being connected to the suction unit via the suction unit flow path and being connected to the compression unit via the compression unit flow path; a discharge unit flow path (130,230,430) configured to connect the cylinder space (140,240) to the discharge unit; a valve (150,250,350,450) disposed to be movable back and forth in the cylinder space (140,440) to open and close the bypass flow path according to a difference between a discharge pressure of the discharge unit and a suction pressure of the suction unit, wherein the valve (150,250,350,450) is configured to move in a first direction toward the suction unit flow path (110,410) to cut off the suction unit flow path (110,410) from the compression unit flow path (120,420) to thereby close the bypass flow path (100,200), and to move in a second direction, opposite to the first direction, to connect the suction unit flow path (110,410) and the compression unit flow path (120,420), characterised in that said movement in the second direction is toward the discharge unit flow path (130,230,430) and the valve (150,250,350,450) includes a first side compressed by the suction pressure of the suction unit and a second side compressed by the discharge pressure of the discharge unit, the first and second sides being on opposite sides of the valve (150,250,350,450), wherein the valve (150,250,350,450) further comprises an opening unit on a lateral side of the valve (150, 250, 350, 450) between said first and second sides, and the bypass flow path (100, 200, 400) is opened and closed by said opening unit.