Head slider having a trapezoidal shape

A magnetic head slider includes a pair of rails (54,56) formed on a disk opposing surface opposed to a magnetic disk, each of the rails having a flat air bearing surface for generating a flying force during rotation of the disk, a slit (58) formed between the pair of rails (54,56), at their air inlet end portions (52A), and a groove (60) defined between the pair of rails (54,56), which is continuous to the slit (58) and wider than the slit, for expanding the air once compressed to generate a negative pressure. The magnetic head slider further includes an electromagnetic transducer (62) formed on an air outlet end (52b) at a position where one of the rails is located. The slider has a trapezoidal shape such that its air inlet end (52A) is narrower than its air outlet end (52b).