PURPOSE: To improve the dimensional accuracy of a gap depth and to stabilize electromagnetic transforming characteristic by adhering a head slider having a sliding face to only one face of the head core, and making the other face to be observed by the gap depth.

CONSTITUTION: The head slider 4 is adhered to only one face of the head core 3, the other face is made a face capable of observing the gap depth of the head core 3. When the grinding part is ground, at the time when the dimension δ2 of the gap depth becomes a prescribed dimension, the grinding is completed without the need for managing the dimension D and, moreover, the dimension δ2 is set with high accuracy.