A magnetoresistance effect has a lamination structure comprising a free layer including at least two ferromagnetic layers, a pinned layer including two ferromagnetic layers; and at least one nano-contact portion composed of a single ferromagnetic layer and disposed between the free layer and the pinned layer. A distance between the free layer and the pinned layer, i.e., thickness of the nano-contact portion in the lamination direction, is not more than Fermi length, preferably less than 100 nm.