A magnetostrictive torque sensor includes a single magnetostrictive film disposed on a steering shaft, and first and second coils for detecting changes in a magnetic property of the magnetostrictive film. The single magnetostrictive film includes a first anisotropic region and a second anisotropic region, having respective magnetic anisotropies inverse to each other. The first coil is disposed in confronting relation to the first anisotropic region, whereas the second coil is disposed in confronting relation to the second anisotropic region.