The present invention provides a magnetic force property measuring method and a magnetic force property measuring device. Even an Nd series ferromagnetic material with a large retentiveness, also can simply measure fluctuation of property of the magnetic material with a low cost through a small-sized device, and can judge a magnet with a poor thermal reducing magnetic property. The magnetic force property measuring device comprises: a magnetic field generation mechanism used for injecting magnetic flux generated by the magnetic field generation mechanism into the ferromagnetic material which is used as a measured object, in order to measure the magnetic force property of the ferromagnetic material; a magnetic pole of the magnetic field generation mechanism, which is configured with the ferromagnetic material used as the measured object with a gap therebetween; a load delivering mechanism connected with the ferromagnetic material used as the measured object; and a load sensor used for measuring a force applied
