PURPOSE: To reduce the number of components and miniaturize a device by coating a material with a low friction coefficient and good abrasion resistance on the surfaces of an outer yoke and an inner yoke faced to the outer periphery and the inner periphery of a cylinder tube.

CONSTITUTION: A driving magnet train 2 is inserted into a cylinder 1 slidably in the axial direction. As the driving magnet train 2 is slid in a cylinder tube 4 by the fluid pressure, a driven magnet train 3 follows via the magnetic force action. Fluoropolyimede resin with a low friction coefficient and good abrasion resistance is coated on surfaces of an outer yoke 18 and an inner yoke 9 faced to the outer periphery and the inner periphery of the cylinder tube 4 about 0.1-0.2mm thick to obtain a bearing function. The number of components can be reduced, the device is miniaturized, and the cost can be reduced.