A disk drive including a negative pressure type head slider having a transducer for reading/writing data from/to a disk having a plurality of tracks, and an actuator for moving the head slider across the tracks of the disk. The actuator includes an actuator arm rotatably mounted on a base of the head slider, a suspension fixed at a base end portion thereof to a front end portion of the actuator arm, and the head slider mounted on a front end portion of the suspension. The head slider includes a front pad having a raised surface and a step surface lower in level than the raised surface, the transducer formed near the air outlet end, and a first groove for generating a negative pressure by expanding air once compressed at the front pad. The bottom surface of the first groove is formed with a plurality of second grooves continuously extending from the downstream side of the front pad to the air outlet end. The second grooves are spaced from each other in the transverse direction of the head slider.