A magnetoresistance effect element having a magnetoresistance effect film and a pair of electrode, the magnetoresistance effect film having a first magnetic layer whose direction of magnetization is substantially pinned in one direction, a second magnetization layer whose direction of magnetization changes in response to an external magnetic field, a nonmagnetic intermediate layer located between the first and second magnetic layers, and a film provided in the first magnetic layer, in the second magnetic layer, at an interface between the first magnetic layer and the nonmagnetic intermediate layer, and/or at an interface between the second magnetic layer and the nonmagnetic intermediate layer.