A magnetic head slider suitable for a disk drive measuring 1.8 inches or less in disk size incorporates preventive measures against the decreases in lifting force that occur in small sliders with a slider width of 0.8 mm or less. The present invention improves the inclination margins of the flying slider in a rolling direction at the lowest flying point, and achieves low flying height and stable flying. The slider is constructed with stepped surfaces on the slider's leading-side flying surface formed up of shallow-grooved surfaces and a deep-grooved surface so that a trailing-side width W2 between the stepped surfaces is smaller than a leading-side width W1.