PURPOSE: To efficiently perform the work by the optimum motion by selectively performing either one of reciprocating revolving motion and reciprocating linear motion and selecting one of both motions corresponding to an object to be erased.

CONSTITUTION: The moving direction of a drive shaft 3 is selected by operating the change-over switch of the rotary direction of a motor 2 and the motor 2 is operated. At the time of work erasing a fine part, a mounting cylindrical part 4 is set so as to be aligned with the drive shaft 3 on a straight line and the drive shaft 3 is subjected to reciprocating revolving motion around its axis. In the case of the revolving motion, an eraser member 9 receives the counteraction from paper being a working object fixed positionally and rolls on the paper to be ready to move. In order to prevent rolling, a housing 1 is firmly grasped to prevent the positional change of the erasure member 9. In the case of reciprocating revolving motion, the erasure member 9 cyclically changes in its rotary direction at a pressed position and prevented from the rolling on the paper. Therefore, it is unnecessary to firmly grasp the housing 1 and the erasure member 9 can be used in a natural state.