A concave portion is formed on the end surface of a main magnet pole layer
on the trailing side. A convex portion is formed on the end surface of a
return yoke layer on the leading side, which opposes the concave portion
formed on the end surface of the main magnet pole layer on the trailing
side, and the distance (gap length) between the main magnet pole layer
and the return yoke layer in the direction of the film thickness is
constant. Consequently, the magnetic field generating from the main
magnet pole layer toward the recording medium is appropriately prevented
from isotropically spreading in the trailing direction, and the width of
magnetization reversal between the recording patterns, which are
magnetized reversely from each other, can be reduced over the entire
area.