PURPOSE: To accurately and smoothly input position coordinates and moving quantity by keeping a contact with a turning sphere and fitting in a member to clean the surface of the sphere at the holding part of the sphere freely attachably and detachably.

CONSTITUTION: A freely opening and closing hatch 11 is provided at the upper part of the main body of a mouse 1, and a pressure bar spring 12 is fitted to the lower surface side of the hatch 11. On the other hand, a sphere 2 is held freely rotatably by a sphere holder 13, a through hole 14 is drilled at a part equivalent to the lower part of the hatch 11 on the holder 13, and a cleaning member 15 to keep contact with the surface of the sphere 2 is idly fitted into the through hole 14. When the hatch is made into a closing state, since the cleaning member 15 is inclined to the upper surface of the sphere 2 by the pressure bar spring 12, the dusts which stick to the sphere 2 and are rolled into the sphere 2 can be wiped off by the tip part of this cleaning member 15, and the sphere 2 can be cleaned automatically during a scanning action without decomposing the main body of the mouse 1.