Embodiments of the invention prevent the reduction of the flying height of a magnetic head slider at a high altitude and thereby to improve the reliability of a magnetic disk drive. In one embodiment, a magnetic head slider has an air inlet end, an air outlet end, and an aerodynamic structure (air bearing surface). The aerodynamic structure includes: a plurality of inlet rails respectively having inlet rail surfaces; an outlet rail having an outlet rail surface flush with the inlet rail surfaces and holding a magnetic head; a bearing surface extending at a predetermined first depth .delta.1 from a reference plane including the inlet and the outlet rail surfaces; a negative-pressure surface extending in a plane at a predetermined second depth .delta.2 greater than the first depth .delta.1 from the reference plane; and longitudinal lands of a predetermined height h formed on the inlet rails. The bearing surface and the inlet rail surfaces extend between the air inlet end and the lands.