To obtain a reactive etching operation which restrains the generation of a polymer substance, can form a fine shape simply and surely, and which can form a magnetic gap in a simple method with high accuracy so as to be perpendicular to the film formation face of a substrate when a magnetic head is manufactured.

A high-selectivity-film formation process wherein a high- selectivity film composed of a metal material which is harder to etch than a material to be etched, in a reactive ion etching operation is formed on the material to be etched a patterning process in which the high-selectivity film formed in the high-selectivity-film formation process is patterned to be in a prescribed shape, a novolak resin-based resist formation process in which a resist composed of a novolak resin-based material is formed on the high- selectivity film patterned to be in the prescribed shape in the patterning process, and an etching process in which the material to be etched is etched by the reactive ion etching operation while the high-selectivity film patterned to be in the prescribed shape in the patterning process is used as a mask, are provided.