A magnetic field detecting element comprises: a stack which includes first, second and third magnetic layers whose magnetization directions depend upon an external magnetic field, the second magnetic layer being positioned between the first magnetic layer and the third magnetic layer, a first non-magnetic intermediate layer sandwiched between the first magnetic layer and the second magnetic layer, and a second non-magnetic intermediate layer sandwiched between the second magnetic layer and the third magnetic layer, wherein the stack is adapted such that sense current flows in a direction that is perpendicular to a film surface thereof; and a bias magnetic layer which is provided on a side of the stack, the side being opposite to an air bearing surface of the stack.