After both an ABS and a back surface of a slider are lapped, a one-surface lapping resulting in balanced compressive stresses of the ABS is performed resulting in unbalanced stresses to make the ABS flat while warping the ABS. At this stage, the slider deforms by changing the back surface in a convex shape, and the ABS itself is maintained flat by the lapping. Thereafter, a one-surface lapping of the back surface is performed to reduce the compressive stresses therein and make the back surface flat while warping the back surface. The slider deforms by changing the ABS in a convex shape and a positive crown on the ABS is formed. The ABS can be lapped flat, and in addition the crown can be formed. Reliability of data read/write can be improved.