PURPOSE: To provide the simple and economical structure of a rotation detector by rotating the rolls magnetized by multiple poles in response to the rotation of a global manipulator body and detecting directly the rotations of these rolls by a magnetic sensor.

CONSTITUTION: A rotatable global manipulator body 1 is positioned at the opening part 9A of a printed circuit board 9. Then the rolls 2-5 which are magnetized by multiple poles are rotated by the rotation of the body 1. The rotations of the rolls are directly detected by the MR elements set opposite to each roll and then sent out as the detected signals on which the change of the electric resistance is reflected. For instance, the X direction components are directly detected and sent out by the MR elements set opposite to the rolls 2 and 4, and the Y direction components are directly detected and sent out by the MR elements set opposite to the rolls 3 and 5 respectively. Thus it is possible to detect the rotation of the body 1 by simple constitution where the rolls 2-5 are combined with the MR elements.