PURPOSE: To carry out switching operation easily in a short time when a bead ring whose peripheral length is slightly different is to be molded.

CONSTITUTION: When a bead ring B whose peripheral length is slightly different is to be molded, an attaching position of a stopper 58 in the axial direction with respect to a main axis 12 is changed and a radial outer edge limit (radial position of a molding groove 55) of a moving segment 30 is only changed. Accordingly, operation will be simple and stop time of a molding device will be almost unnecessary. In addition, other member for changing the peripheral length is unnecessary, so that a storing place for it will be unnecessary, thereby saving space.