PURPOSE: To make it possible to hold a pallet parallel to a rail constantly by holding the rail with rollers provided to rotary arms connected coaxially, as well as holding the rail with a pair of rollers.

CONSTITUTION: A pallet 3 moves guided on a rail being held by a pair of rollers 4 to hold the rail 1, and guide rollers 7a and 7c journalled to rotary arem 5a, 5b, 6a, and 6b which are held rotatable by the shafts 31 and 32 of the rollers 4 are energized to an elastic member 9 so as to hold the side surfaces of the rail. As a result, the pallet 3 can move by maintaining a specific angle to the rail 1, and a driving pinion 8 geared with a rack 2 provided to the rail 1 can be rotated by a desired driving means, so as to carry out the conveyance and the positioning.