PURPOSE: To provide a supporting device for a guide roller, which enhances the accuracy of clamping of the guide roller and controllability at which the roller is gripped and released.

CONSTITUTION: A supporting device for a guide roller has a chuck (collet chuck 4) for holding the support shaft of a guide roller 2 to be supported and a chuck switching mechanism 6 which in conjunction with a rotation means (pulley 34) causes the guide roller being held by the chuck to rotate together with the chuck and is installed in such a manner as to be capable of moving back and forth with respect to the center of the chuck so as to close the chuck when moved in one direction and open the chuck when moved in the other direction.