A magneto-resistive effect (MR) element includes a magneto-resistive (MR) stack with a magnetization free layer, a bias magnetic field application layer positioned on a side of the MR stack, and an insulation film insulating the bias magnetic field application layer. The bias magnetic field application layer includes hard magnetic layer positioned on the side of the magnetization free layer and formed of iron-platinum (FePt) alloy and Pt seed layer provided between the MR stack and the hard magnetic layer and on a lower surface of the hard magnetic layer in contact manner with the hard magnetic layer and formed of platinum (Pt). The insulation film is a MgO insulation film formed of oxide magnesium (MgO), provided on a surface of the Pt seed layer in contact manner with the Pt seed layer, the surface being opposite to another surface of the Pt seed layer contacting the hard magnetic layer.