A magnetic head device includes a slider with a facing side and a magnetic function part. The facing side of the slider includes a front positive pressure surface located close to a leading end of the slider, a rear positive pressure surface located close to a trailing end of the slider, and a pair of side positive pressure surfaces located closer to the trailing end than the front positive pressure surface and disposed at both sides of a longitudinally extending centerline. Air inlet grooves for introducing air into the side positive pressure surfaces are each disposed in front of each side positive pressure surface. Each air inlet groove extends between the front positive pressure surface and a corresponding side face of the slider and opens toward a leading end face of the slider.