PURPOSE: To obtain an information disk of less eccentricity by such an arrangement wherein a radial ray permeable base board having a hole for positioning is coupled with a metal mold having a protruded point for positioning at its center and also having uneven information signals, and radial ray setting resin is injected into between the metal mold and base board and between the protruded point and hole, and the resin is then hardened.

CONSTITUTION: A metal mold 1 having uneven information signals is fixed to a metal mold main body 2 with a center pin 3. On the other hand, a radial ray permeable base board 4 is held by a base board holder 5 to be freely installed and removed, and the base board holder 5 is coupled with a ram 7 so that it can be moved up and down along the ram and a conical protrusion 8 is formed at the end of the ram 7. Further, the conical protrusion 8 is opposed to the tapered part of the center pin 3. Next, radial ray setting resin is injected into a space 15 through a resin passage 14 and the resin layer 16 is hardened by illuminating radial rays from a source of radial rays 17. Thus a disk of less eccentricity 18 can be obtained.