To prevent the shaft portion of a direct-acting motor from contacting with its moving portion, and perform by the direct-acting motor the movement of a table or an optical unit accurately at a high speed.

The direct-acting motor has a shaft portion 14a including inside a cylindrical magnet, and has a moving portion 14b including inside a coil surrounding the shaft portion 14a whose inner diameter is larger than the outer diameter of the shaft portion 14a. Contact preventing mechanisms are so attached to both the ends of the moving portion 14b as to prevent the shaft portion 14a from contacting with the moving portion 14b when the shaft portion 14a vibrates. Each contact preventing mechanism has a plurality of rollers 31, a plurality of roller holding members 32 for holding in a rotatable way the respective rollers 31, and a roller attaching member 33 provided with a plurality of guiding grooves 33a for guiding the respective roller holding members. Hereupon, each roller holding member 32 is so positioned in each guiding groove 33a of the roller attaching member 33 as to interpose the surface of the each roller 31 between the outer diameter of the shaft portion 14a and the inner diameter of the moving portion 14b.