A magnetic head slider comprises a slider body comprising a base portion made of an altic material and an element-forming portion, made of alumina, having formed thereon magnetic conversion elements. Slider-flying rails protruding beyond the surface of the slider body are provided. A first protection film is formed on the surface of the slider body to cover a boundary between the element-forming portion and the base portion to thereby prevent a lubricant of a magnetic disk from depositing on the boundary between the base portion and the element-forming portion. Second protection films are formed on the surfaces of the slider-flying rails to protect the magnetic conversion elements from being corroded and damaged. Further, when pneumatic bearings are provided on the slider-flying rails, third protection films are formed on the surfaces of the pneumatic bearings.