PURPOSE: To provide a positioning device which can devlop a general sheet positioning device, save the space and drive plural positioning members by one drive shaft.

CONSTITUTION: A bearing part 7 is provided on the continuously driven drive shaft 4 arranged parallel to the transport plane of a sheet to be aligned and at right angle to a sheet transport direction A. An aligning roller 5 at an oblique angle α to said sheet transport direction A is installed rotatably on this bearing part 7. This bearing is fixed so as not to rotate and move and the drive shaft 4 is penetrated rotatably. The aligning roller 5 is installed rotationally symmetrical to the drive shaft 4. The drive shaft 4 is connected to the aligning roller 5 mutually by positive couplings 5a, 8. The bearing part 7 having the aligning roller can be installed on the drive shaft 4 and driven by one drive shaft 4.