A magnet holding jig comprises a platform and first and second holders disposed on opposite sides of the platform. The platform is provided with channels, the holders are comb-shaped to define digits and slits, the channels and the slits being aligned to define guide paths for permitting entry of a cutting tool therein, and the holders are also configured as digitate hooks. The holder hooks are in contact with a rare earth magnet block resting on the platform. The holders are pushed inward at their lower portions so as to elastically deform the digitate hook and move it backward and to bring the hook digits in pressure abutment with the magnet block, thereby holding the magnet block in place on the platform.