PURPOSE: To provide a magnetic azimuth finder in which the rotation angle of a moving object is detected by a rotation angle sensor and the signal from the rotation angle sensor is used in picking up signals of a number sufficient for making a compensation for any disturbance out of the digital output signals of a magnetic azimuth sensor thereby to permit the determination of the offset compensation value.

CONSTITUTION: The outputs Vx and Vy from a magnetic azimuth sensor 11 is converted into digital signals (x) and (y) through a multiplexer 12 and an A/D converter 13. A switch S1 is operated to connect to a stationary contact t1. A moving object is provided with a rotation angle sensor 14 of a comparatively high sensing accuracy. The rotation angle sensor 14 delivers rotation angle signals produced throughout 360° rotation of the moving object to a selector circuit 15. Each time a predetermined rotation angle is reached, the digital signal from the A/D converter 13 is stored in the data memory 16. The data thus stored is then sent to a compensation value computing circuit 17, and an averaging processing is performed as a computation start switch 18 is turned on thereby to determine the offset compensation values xo and yo.