Oil supply device (130) for a compressor in a refrigerating system including a cylindrical piece (131) fixed to a lower end of a crankshaft (110) for rotating together with the crankshaft, a propeller (132) fitted inside of the piece for making oil to rise by a relative movement with the piece (131), and rotation prevention means (141) fitted to a bottom end of the propeller (132) for prevention of rotation of the propeller, thereby supplying an adequate amount of refrigerant oil even if the compressor, operative at a low, as well as a high speed, is operated at the low speed.