A spin-valve type magnetoresistive thin film head is provided with a spin-valve type magnetoresistive thin film element which includes a free magnetic layer; an upper nonmagnetic electrically-conductive layer and a lower nonmagnetic electrically-conductive layer sandwiching the free magnetic layer; an upper pinned magnetic layer and a lower pinned magnetic layer formed on the upper and lower nonmagnetic electrically-conductive layers, respectively, the magnetization directions of the upper and lower pinned magnetic layers being fixed; and an upper antiferromagnetic layer and a lower antiferromagnetic layer formed on the upper and lower pinned magnetic layers, respectively; in which a sensing electric current is applied in the direction perpendicular to the fixed magnetization of the pinned magnetic layers, and electrical resistance changes in response to the relationship between the fixed magnetization of the pinned magnetic layers and the variable magnetization of the free magnetic layer.