When a gate voltage is applied, the Schottky barrier width due to the metallic spin band in the ferromagnetic source decreasing, up-spin electrons from the metallic spin band are tunnel-injected into the channel region. However, down-spin electrons from the nonmagnetic contact are not injected because of the energy barrier due to semiconductive spin band of the ferromagnetic source. Only up-spin electrons are injected into the channel layer from the ferromagnetic source. If the ferromagnetic source and the ferromagnetic drain are parallel magnetized, up-spin electrons are conducted through the metallic spin band of the ferromagnetic drain to become the drain current. Contrarily, if the ferromagnetic source and the ferromagnetic drain are antiparallel magnetized, up-spin electrons cannon be conducted through the ferromagnetic drain. A nonvolatile memory composed of MISFETs operating on the above principle is fabricated.