PURPOSE: To simplify considerably the assembling work by bringing the inclined outside peripheral surface of a hub body and the inclined peripheral wall surface of a center through hole into contact with each other to position automatically a disc veneer.

CONSTITUTION: In case of assembling of an optical disc, an inside peripheral spacer 32 and an outside peripheral spacer 25 to which an unhardened adhesive is applied are interposed between two disc veneers 20 and 21 whose recording surfaces 20a and 21a face each other, and an upper hub body 24 and a lower hub body 25 are inserted to center through holes 22 and 23, and this pair of hub bodies 24 and 25 are fastened in plural positions by screws 30 to fit the upper hub body 24 and the lower hub body 25 into the center through hole 22 and the center through hole 23 respectively. According as the upper hub body 24 is fitted into the center through hole 22, an inclined outside peripheral surface 24a and an inclined peripheral wall surface 22a having the same taper angle are brought into contact with each other to set automatically the disc veneer 20 to a prescribed position; and similarly, according as the lower hub body 25 is fitted into the center through hole 23, the disc veneer 21 is automatically set to a prescribed position, and thereby, the concentricity between disc veneers 20 and 21 and hub bodies 24 and 25 are secured automatically.