A geomagnetic sensor including a geomagnetism detection unit; a fuse memory for storing prescribed data according to a state of the electrical cut-off or connection; a correction data writing unit for inputting measurement values of said geomagnetism detection unit during manufacture, for obtaining correction values that correct a temperature property of the measurement values of the geomagnetism detection unit, and for writing said correction values into said fuse memory; a correction data reading unit for reading said correction values from said fuse memory at times of actual use after manufacture; and a correction unit for inputting the measurement values of said geomagnetism detection unit at times of actual use, and for correcting the measurement values of said geomagnetism detection unit based on the correction values read by said correction data reading unit.