To prevent degradation in accuracy of a detected azimuth, resulting from disturbance of magnetism generated in an electronic instrument.

An electronic instrument comprises: a geomagnetism detection part configured to acquire magnetic azimuth data according to geomagnetism at each prescribed time; a changed quantity calculation part configured to calculate a changed quantity of magnetic azimuth data; a storage part configured to store magnetic azimuth data; and an integration part configured to calculate angle data by integrating angle velocities acquired by an angle velocity detecting part. When the magnetic azimuth data and angle velocity are within the range of a threshold, the magnetic azimuth data is used as output azimuth data. If the amount of change or the angle velocity is out of the range of the threshold, the angle calculated by an angle velocity integrating part is used having the point when it falls to the outside of the range of the threshold as a reference point for zero. The result obtained by adding this angle to the newest geomagnetic data stored when the amount of change and the velocity are within the range of threshold is used as an output azimuth.