A pulsar ring is provided with a ring-shaped supporting member and a magnetized member formed into a strip shape and secured to a circumferential face of the supporting member so that N-poles and S-poles are arranged alternately with equal pitches. The length of the circumferential face of the supporting member is set so as to correspond to the length of the magnetized member so that the end portions of the magnetized member are butted to each other without any gap with the magnetic property in the butted portion being maintained to have equal pitches. The magnetized member is magnetized by a magnetizing device, and then affixed to the supporting member.
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