A head positioning system for use with a magnetic disk with outer, middle and inner servo tracks which are radially separated by data tracks. The head positioning system includes a measuring element for measuring deviations of the magnetic head from the outer, middle and inner servo tracks by reading the servo information recorded on each of the servo tracks and generating first, second and third deviation values. The head positioning system also includes a determining element which determines an offset correction value for a targtet data track included in the data tracks in accordance with a quadratic compensation function and the first, second and third deviation values. A fine positioning element positions the magnetic track of the target track according to the offset correction value.