PURPOSE: To improve the reliability of a magnetic card, etc., by heating a recording medium, consisting of laminated magnetic layers differing in Curie temperature and coercive force, at prescribed temperature during reproduction and by performing comparison and arithmetic processing with respect to pieces of reproduced information before and after the heating.

CONSTITUTION: A magnetic recording medium 1 consists of magnetic layers 3 and 5 laminated on a substrate 2 of plastics, etc., with an insulating partition layer 4 interposed, and is further covered with a surface protective layer 6. Control information from an input terminal 7 changes a switch 13 over to a recording R side, and then signals are inputted from an input terminal 6 to a modulator 11 and an artificial modulator 10 and sent to a recording and reproducing head 16 for magnetic recording on the recording medium 1. Recorded information, when reproduced, is sent from the reproducing head 16 to a demodulator 14 and while the recording medium 1 is heated under the control of a heating control circuit 15 when passing between heating rollers 18, the reproduction of the heated recording medium 1 is carried out by a reproducing head 17 to send reproduced information to a demodulator 19. The pieces of information from the demodulators 14 and 19 are supplied to an arithmetic circuit 20 for prescribed arithmetic processing.