According to one embodiment, a head for a disk drive includes a slider including an air-bearing surface having a pair of side edges, a pair of side surfaces, a leading-side end surface and a trailing-side end surface, and a head section provided in the slider. The slider includes a leading step in a leading-side end portion of the air-bearing surface, a deep trench provided downstream side of the leading step, and a trailing step in a trailing side end portion of the air-bearing surface and including the head section built therein, and side trenches having a depth of 100 to 300 nm formed respectively along the pair side edges of the air-bearing surface.