A reception unit receives global positioning system signals transmitted by a plurality of satellites to obtain satellite information. A determination unit determines whether or not a state in which the reception unit receives the global positioning system signals is a predetermined reception state. A positional calculation unit calculates a current position based on ephemeris information and almanac information when the reception state is the predetermined reception state, the ephemeris information including at least six orbital elements and being obtained from satellite information of first and second satellites among satellite information of three satellites, and the almanac information including at least six orbital elements on a general orbit of a third satellite of the three satellites.