[Problem] To provide a magnet evaluating device with a simpler configuration that is capable of evaluating eddy current loss occurring in a magnet. [Solution] A magnet evaluating device 1 evaluates an evaluation magnet 51 by passing the evaluation magnet 51, which is formed by connecting a plurality of magnetic sections 101 with insulating material 103 in between, and a master magnet 55 of the same form through an alternating magnetic field generated by an excitation coil 12, measuring the eddy current occurring in the magnetic section 101 as voltage or current occurring in a detection coil 13 and comparing the measured value for the evaluation magnet 51 and the measured value for the master magnet 55.