To make more strict the resolution of the length and the width of a magnetic bit, reduce the noises level, and enhance reading of a signal by a method wherein a successive connection is formed like a cylinder along a sensor without excessively over-milling a read gap.

A read gap layer 44 of a low ion milling rate material is formed and a MR sensor 46 is formed on the read gap layer 44. The read gap layer 44 is formed with a material having a substantially smaller milling rate than a normal read gap material such as Al2O3, AlN, or the like. A great difference in the milling rates between the sensor 46 and the gap layer 44 forms a boundary 52 of the sensor having a steeper inclination than a surface 55 adjacent to the gap layer. Generally, the steep inclination 52 is formed by prolonging an over-milling time. An extension part in a transverse direction of a boundary is much decreased by the steep inclination 52, and the width of the sensor is defined more strictly, and a bit on a track can be read more accurately.