A magnetoresistance effect film is disclosed. This magnetoresistance effect film comprises a substrate, at least two ferromagnetic thin films stacked one over the other on the substrate with a non-magnetic thin film interposed therebetween, and an antiferromagnetic thin film arranged adjacent to one of the ferromagnetic thin films. The antiferromagnetic thin film is a superlattice formed of at least two oxide antiferromagnetic materials selected from NiO, Ni.sub.x Co.sub.1-x O (0.1.ltoreq.x.ltoreq.0.9) and C.sub.o O. A biasing magnetic field Hr applied to the one ferromagnetic thin film located adjacent the antiferromagnetic thin film is greater than coercive magnetic force Hc.sub.2 of the other ferromagnetic thin film.