A scroll compressor including a housing (10, 20, 30), a driving motor accommodated in the housing, an orbiting scroll orbited by the driving motor, a fixed scroll disposed in the housing and forming a compression chamber together with the orbiting scroll, a suction port provided in the housing at one side of the driving motor and configured to suck refrigerant, an oil separator provided in the housing at one side of the fixed scroll and configured to separate oil from the refrigerant discharged from the fixed scroll, and a discharge port configured to discharge the refrigerant from which oil has been separated in the oil separator to an outside of the housing, the scroll compressor comprising: an intermediate housing disposed in the housing and rotatably supporting a rotary shaft of the driving motor; a back pressure chamber provided in the intermediate housing at one side of the orbiting scroll; a first back pressure seal member disposed in the intermediate housing to surround a periphery of the back pressure chamber and configured to seal a gap between the orbiting scroll and the intermediate housing; a second back pressure seal member disposed in the intermediate housing at one end of the back pressure chamber and configured to seal a gap between the rotary shaft and the intermediate housing; characterised in that a plurality of anti-rotation rings is disposed in the intermediate housing at an outer side of the first back pressure seal member; and a plurality of anti-rotation pins is provided in the orbiting scroll and inserted into the plurality of anti-rotation rings, respectively; an oil supply passage through which the oil separated by the oil separator moves to the back pressure chamber, is provided between the oil separator and the back pressure chamber; and an orifice pin is disposed in the oil supply passage, the orifice pin including a tip portion, a middle portion, and a rear end portion which sequentially increase in diameter. an intermediate housing disposed in the housing and rotatably supporting a rotary shaft of the driving motor; a back pressure chamber provided in the intermediate housing at one side of the orbiting scroll; a first back pressure seal member disposed in the intermediate housing to surround a periphery of the back pressure chamber and configured to seal a gap between the orbiting scroll and the intermediate housing; a second back pressure seal member disposed in the intermediate housing at one end of the back pressure chamber and configured to seal a gap between the rotary shaft and the intermediate housing; characterised in that a plurality of anti-rotation rings is disposed in the intermediate housing at an outer side of the first back pressure seal member; and a plurality of anti-rotation pins is provided in the orbiting scroll and inserted into the plurality of anti-rotation rings, respectively; an oil supply passage through which the oil separated by the oil separator moves to the back pressure chamber, is provided between the oil separator and the back pressure chamber; and an orifice pin is disposed in the oil supply passage, the orifice pin including a tip portion, a middle portion, and a rear end portion which sequentially increase in diameter.