PURPOSE: To provide a method for manufacturing a thin film magnetic head capable of reducing the dispersion in a gap depth GD between respective elements and obtaining a required characteristic.

CONSTITUTION: A first monitor pattern 15 consisting of an isosceles triangle (a length of the base (a)= height (h)) arranging the base 15a in parallel with the arrangement direction of a magnetic head element and where the vertex 15b arrives at one side boundary line L1 of an allowable range of the GD is formed adjacent to respective magnetic head elements 11 on a substrate 10. Further, a rectangular second monitor pattern 16 having a thickness (t) coinciding with the width of the allowable size of the GD is arranged so that the upper side 16a and the lower side 16b coincide with both boundary lines (L2, L1) of the allowable range of the GD close to that. Then, an additional grinding amount is obtained from the width of the exposure part of the pattern 15 onto a grinding surface, and the judgement whether a nondefective or not is performed by the presence of the exposure of the pattern 16. That is, the GD is controlled simply only by viewing the grinding surface (without measuring a size, etc.).