To perform the centering of a circular-ringed thine plate easily and accurately at the time of combining it with a circular-ringed metal plate together, etc.

This device is provided with a disk 11 formed with the appropriate numbers of pieces of spiral grooves being point-symmetrical to the center, installing the appropriate numbers of pieces of centering parts 14 installed with respective slide pins 16, erecting each sizing pin 15 in one side and inserting each spiral groove 12 into the other side free of sliding motion, and each of sliding part 17 sliding the slide pins 16, sliding in each spiral groove 12, in the vertical direction, and thus a centering device of a circular-ringed thin plate. In this constitution, the spiral groove 12 is made up into such a form as widening the slide pin 16 to the outside when the disk 11 is rotated in one direction, but narrowing it inside when it is rotated in the other direction. With this, the sizing pin 15 or being integral with the slide pin 16 becomes the same core and the same size with the center of the disk 11, whereby the centering of the circular-ringed thin plate 1 is accurately performed.