The magnetoresistance effect element includes a semiconductor layer, a first ferromagnetic layer and a second ferromagnetic layer. The semiconductor layer has a first region, a second region, and a third region. The first ferromagnetic layer is provided on the first region, the second ferromagnetic layer is provided on the second region, and the third region is sandwiched between the first region and the second region in the first direction. The third region has n-type (or p-type) conductivity, and crystal orientations of the semiconductor material in the direction are substantially the same in the first region, the second region, and the third region. An interatomic distance of the first region in the first direction in an upper surface neighboring region including the upper surface is larger (or smaller) than an interatomic distance of the third region in the first direction in an upper surface neighboring region including the upper surface.