PURPOSE: To easily grasp whether the current progressing direction coincides with the direction to the target spot or to what extent the current progressing direction is deviated from the direction to the target spot by outputting a direction setting signal making it possible to preset the progressing direction to the target spot and corresponding to the set direction.

CONSTITUTION: The titled device is provided with a direction setting circuit 2, a direction detection circuit 14, a directional difference calculation circuit 28 and a directional difference display circuit 44. Then, the circuit 2 consists of an external operation member 4 outputting an operation signal, a chattering preventive circuit 6 and a counter 8. Further, the circuit 14 consists of a terrestrial magnetism sensor 16 detecting the progressing direction and an amplifier 18 amplifying a detected signal outputted from the sensor 16 and the like and further, the circuit 28 consists of a ring counter 30 and a comparison circuit 42 and the like and further, the circuit 44 consists of a driver 46 and a display 48 and the like. Then, the circuit 2 sets the progressing direction to the target spot. Further, the detector 14 detects the progressing direction. The difference between the set direction and the progressing direction is calculated every prescribed time and the calculated directional difference is displayed on the circuit 44.