A magnetic head contains a write magnetic head and a read magnetic head. The write magnetic head includes a lower core layer, an upper core layer arranged over the lower core layer, and a coil layer for applying a magnetic field to the lower and upper core layers. The read magnetic head includes an upper shield layer, a lower shield layer, and a reproducing device arranged between the upper shield layer and the lower shield layer. The upper shield layer has a dimension A in a direction of track width and a dimension B in a direction of height and has an aspect ratio B/A ranging from 0.6 to 1.2. The dimension A ranges from 75 .mu.m to 150 .mu.m.