To accurately position a workpiece by preventing the workpiece W from inclining onto the opposite side to the reference roller side from a conveying direction to cause the left side face of the workpiece to separate from the reference roller 17 during the conveyance of the workpiece.

This roller conveyor device is so constituted that the support positions of a plurality of reference rollers 17 are respectively positioned in reference positions in the direction orthogonal to the conveying direction and that rotating shafts 15 of a plurality of carrier rollers 11 are respectively tiltable by a slight quantity in the horizontal direction to incline the direction of peripheral speed of the upper parts of a plurality of carrier rollers 11 onto the reference roller 17 side from the conveying direction. A tilt operating means 25 is provided for tilting a plurality of carrier rollers 11 by a slight quantity in the horizontal direction.