In a stepping motor, stator yokes have a plurality of comb-tooth-shaped magnetic poles 5b, 6b, 7b and 8b in such a manner that the comb-tooth-shaped magnetic poles are opposed to each other coaxially to a rotor portion made from a permanent magnet magnetized to have multiple magnetic poles, and an excitation coil is fitted on the external circumference of the stator yokes and the excitation coil and the stator yokes are surrounded by a frame yoke. Each of the yokes is formed of an Fe—Cr alloy having a predetermined ferrite single-phase structure so that occurrence of eddy currents in an alternating-current magnetic field is suppressed.