A thin film magnetic head has a magneto-resistive (MR) effect element including an MR effect film formed by sequentially layering a magnetic pinned layer, a nonmagnetic layer and a free layer, and a pair of bias magnetic field application layers formed at junction tapered parts formed on both end parts of the magneto-resistive effect film in the width direction via insulating layers. Further, magnetic pinned layer oxidized films whose thickness is Hx (unit: nm) are disposed on end parts of the magnetic pinned layer at the junction tapered parts, free layer oxidized films whose thickness is Hf (unit: nm) are disposed on end parts of the free layer at the junction tapered parts, and the oxidized films are configured such that the thickness ratio (Hx/Hf) is not more than 0.5. With this configuration, the bias magnetic filed application layers effectively apply a vertical bias magnetic filed to the free layer, resulting in that the thin film magnetic head is realized having a large MR ratio, a small deviation σ of MR waveform asymmetry, and excellent reliability.