PURPOSE: To eliminate the need to spread sensors in a place where a spherical body moves by moving the spherical body by a combination of the pattern on the surface of the spherical body and the sensors which are close to it.

CONSTITUTION: The spherical body 2 is fitted to a pen tip part 1. Further, N optical fiber sensors S1-SN are circularly arranged above the spherical body 2. Projecting elements and photodetecting elements are fitted to the tail ends of the optical fibers and convert the light and shade on the surface of the spherical body into electric signals. The spherical body 2 is moved by the combination of the pattern on the surface of the spherical body 2 and the sensors S1-SN which are close to it, so the sensors need not be spread in the place where the spherical body 2 moves. This results in that interaction with information equipment can be done by merely tracing a plane without being aware of the input place when this graphic input device is used, so thinking is not interrupted and the interaction with the information equipment becomes possible.