PURPOSE: To execute the function extension for varying size of a line in accordance with pressing force to the device, etc., and to improve the operability by providing a converting mechanism for converting the motion of a main body into a rotation of a ball, a rotation quantity detecting mechanism, and a pressure detecting mechanism for detecting the force for pressing the main body.

CONSTITUTION: On the bottom face 1 of a housing, a ball 2 and a projection 3 are provided, and the ball 2 is rotated by a movement of a pointing device (main body). The rotation in the X axis direction of the ball 2 is transferred to a first transducer 6 through a first bar 5 which comes into contact with the side face of its right, and from the transducer 6, an electric signal corresponding to the speed of revolution of the bar 5 is generated. The rotation in the Y axis direction of the ball 2 is transferred to a second transducer 8 through a second bar 7 which comes into contact with its upper side face, and from the transducer 8, an electric signal corresponding to the speed of revolution of the bar 7 is generated. Also, the projection 3 comes into contact with a pressure sensor 4, and when the pointing device (main body) is pressed, its pressure is detected. In such a way, the function extension for varying size of a line in accordance with pressing force to the pointing device, etc., can be executed, and the operability can be improved.