To provide a separator which significantly reduces the manual operations for separating granular ferromagnetic parts containing copper from other ferromagnetic parts.

The magnetic separator includes two or more solenoids 6 and 7 arranged inside a rotatable drum 1 and connected to a direct-current power supply 8 for generating a magnetic field suitable for separating a ferromagnetic material; wherein voltage is controlled so that the direct-current power supply supplies a current maintained at a substantially constant value to the solenoids, and the magnetic force obtained by the magnetomotive force per unit volume resulting from the magnetic field generated by the solenoids is larger than the mean gravity of iron, but smaller than the specific gravity of the ferromagnetic material containing at least 12 wt.% of copper.