PURPOSE: To detect the moving direction of a moving body accurately and easily by arranging two Hall elements at right angles to each other and oscillating them as prescribed, and detecting the directions wherein the Hall elements are directed from their outputs.

CONSTITUTION: Hall elements 1A and 1B arranged at right angles to each other are rotationally oscillated simultaneously by a device 3, providing a rotational oscillation. The outputs of the Hall elements 1A and 1B are applied to synchronous rectifiers 5A and 5B through narrow-band amplifiers 4A and 4B. The outputs of those synchronous rectifiers 5A and 5B are sent to a code detecting and comparing circuit 6, whose output is used to display the directions wherein the Hall elements 1A and 1B are directed on a display device 7.