A flying head slider utilizing a negative pressure according to the invention has a front end, a rear end, and an air bearing surface directed to face a rotating recording medium. The air bearing surface includes a pair of side rails extending on both sides of the air bearing surface from the front end in the longitudinal direction of the slider, a center rail provided at the center of the air bearing surface in the transverse direction and extending from the front end to the rear end in the longitudinal direction of the slider, a cross rail extending in the transverse direction of the slider to connect the pair of side rails and the center rail to each other near the front end, a pair of recesses defined by the pair of side rails, the center rail and the cross rail, communicating grooves for communicating the pair of recesses with the front end, and a head mounted on a rear end surface of the center rail. The pair of side rails, the center rail and the cross rail lie substantially in the same plane. The pair of side rails are spaced from the rear end and are terminated at oblique edges in agreement with oblique lines extending from side edges of the slider to the center of the center rail at its rear end. The pair of side rails each has a width shape which is gradually narrowed from the front end toward a narrow portion located in a vicinity of a center of the slider, and is gradually spread from the narrow portion toward the rear end. The center rail is extended from the front end with substantially a constant width, followed by a width shape gradually spreading toward the rear end.