An offset calculation circuit comprising a data obtaining unit for sequentially obtaining two-axis or three-axis magnetic detection data as a set of data points of a two-axis coordinate system or a three-axis coordinate system; an offset recording unit for recording offset components of the magnetic detection data as an offset point of the two-axis coordinate system or the three-axis coordinate system; and an offset calculation unit for calculating a first reference line or a first reference plane put between first and second data points among the set of data points, and subsequently moving the offset point recorded in the offset recording unit in a direction toward the first reference line or the first reference plane to calculate a first offset candidate point.