A magnetic head has a base, and a magneto-resistive device supported by the base. The magneto-resistive device includes a magneto-resistive layer formed on one surface side of the base, and a first film. The first film is formed to be in contact with an effective region effectively involved in detection of magnetism in the magneto-resistive layer on both sides or one side of the effective region in a track width direction without overlapping with the effective region. The track width direction is substantially parallel to a film surface of the magneto-resistive layer. The first film is a single-layer film or a multiple-layer film. The first film includes a soft magnetic layer which does not form part of a layer for applying a biasing magnetic field to the free layer. The soft magnetic layer contributes to a reduction in side reading.