PURPOSE: To obtain uniform and fine recurrent reflection by forming a reflecting layer by adhering glass beads on the surface of a metallic plate so as to burying these glass beads into adherent to obtan a glass beads reflecting board and punching the reflecting board based upon a prescribed shape to mold a semispherical reflector having its reflecting layer on its surface.

CONSTITUTION: The reflecting layer 8 of a glass bead reflecting board 1 is obtained by uniformly adhering many glass beads with adherent 5 on the surface of base board 2 through foundation coat 3 and covering these glass beads with transparent protecting coat 6. The reflecting board 1 is punched based upon a prescribed shape by press working to mold a semispherical reflecting board having its reflecting layer on its external peripheral surface. Subsequently, two semispherical reflectors 7 molded as shown in the drawing are joined airtightly to obtain a hollow buoy having a reflecting layer 7 on the whole external surface of the buoy.