Abstract: A magnetoresistance effect element including a substrate and at least two magnetic thin layers which are laminated with interposing a non-magnetic thin layer therebetween on said substrate, wherein adjacent magnetic thin layers through the non-magnetic thin layer have different coercive forces and each of the magnetic thin layers and the non-magnetic layer has a thickness of not larger than 200 .ANG., which has a large magnetoresistance ratio of several % to several ten % at a small external magnetic field of several Oe to several ten Oe and can provide a MR sensor having a high sensitivity and a MR head which achieves high density magnetic recording.