Provided is an offset estimation device, and the like, for promptly estimating the offset of magnetic data output by a geomagnetic sensor. An offset estimation device (40) estimates the offset of magnetic data output by a magnetic sensor (20), and comprises the following: a rotational axis calculation unit that acquires a plurality of magnetic data items detected by the magnetic sensor and a plurality of angular velocity data items corresponding to the rotation of the offset estimation device (40), and that, in a three dimensional coordinate space in which a plurality of magnetic data items are arranged, finds on the basis of a discretionary magnetic data item group from among the plurality of data items and each magnetic data item corresponding to the magnetic data item group, a plurality of rotation axes that pass through the center of a plane that passes through the magnetic data item group and that express a line perpendicular to the plane; and an offset estimation unit for estimating the offset of the magnetic data output by the magnetic sensor (20) on the basis of the plurality of rotation axes.