A sintered body for a magnetic head slider, which can reduce differences in level of an air bearing surface while yielding a high strength, a magnetic head slider using the same, and a method of manufacturing a sintered body for a magnetic head slider are provided. The sintered body of the present invention is a sintered body comprising alumina crystal grains and a thin film containing carbon provided at a grain boundary between the alumina crystal grains, whereas the alumina crystal grains have an average particle size of 0.05 to 0.5 .mu.m.