PURPOSE: To assemble molds for lens array by a method in which metal pieces are thrust into the through holes of a mold plate and temporarily clamped by screws, the eccentricity of each metal piece is corrected, and the metal pieces are fixed with an adhesive in such a way as to avoid the inclination of the optical axis of the concaved faces of the metal pieces.

CONSTITUTION: Under the condition that the eccentric direction of the metal pieces 10 is corrected and arranged toward the longitudinal direction of a mold plate 5, the metal pieces 10 are thrust into the through holes 5a of the mold plate and temporarily clamped with screws 9. An adhesive 14 is packed into the space between the metal pieces 10 and the through holes 5a of fix the metal pieces to the mold plate. The inclination of optical axis of the concaved faces 10a can be avoided and the occurrence of play can be prevented by the adhesive 13.