PURPOSE: To obtain a thin film magnetic head having a low step structure at a high yield without deteriorating the magnetic characteristic thereof by using a sintered body having a grain size of a specific length or below and Vickers hardness in a limited range for a substrate and adopting a Co-base amorphous alloy for the magnetic film.

CONSTITUTION: An Al2O3-TiO2 substrate having 1,000 Vickers hardness and 5mm grian size is used and recesses are provided thereto by a dicer of which the blade is worked to a prescribed shape. A thin film of a Co-Nb or Co-Nb-Zr alloy is formed by a sputtering method under 4×10-6Torr residual gaseous pressure and ≤2×10-3Torr gaseous Ar pressure and at ≤350°C substrate temp. to form a lower magentic layer 2. An upper magnetic layer 6 is further formed of a thin Co-Nb or Co-Nb-Zr alloy film similarly to the lower magnetic layer under the same conditions and Al2O3 is formed thereon under the condition of ≤8×10-4 Torr residual gaseous pressure, 3×10-3Torr gaseous Ar pressure and 50W100/ min sputtering speed in the case of sputtering method. The substrate is subjected finally to lapping down to a prescribed thickness after formation of a protective film and a protective plate 8 made of the same material as the material for the substrate 1 is adhered to the substrate in the state shown in the figure.