There is provided a method for manufacturing a method for manufacturing an optical element, wherein a mold-press molding is performed by use of a material body having a prismatic shape to form a light transmission part and a flange of the optical element, the flange extending outward from the light transmission part. In the manufacturing method, only a corner of the material body to be subjected to a mold transfer to provide an edge face of the flange.

In the conventional direct press method, it was difficult to control the weight of molten glass gob when manufacturing a small precision glass component and thus the weight of the glass gob varies widely. Accordingly, the problem is that the precise molding cannot be expected stably. As a solution, the present invention provides a mold for molding a glass-made optical component and a manufacturing method using the mold, the mold comprising: a female mold which has a lower mold of a molding mold for molding the glass-made optical component on an outer peripheral portion of a concave surface of the female mold; a male mold which has a convex surface combined with the concave surface of the female mold; and a ring mold which is arranged on an outer peripheral portion of the male mold, the ring mold having an upper mold of the molding mold for molding the glass-made optical component, wherein molten glass gob introduced into the concave surface of the female mold is configured to be pressed from above by the male mold having the convex surface so that the molten glass gob is injected into a space formed between the lower mold and the upper mold of the molding mold.

A method of manufacturing a glass molded product includes the steps of preparing a lower die including a lower die surface and a space forming surface formed to extend downward away from an outer edge end portion of the lower die surface with the outer edge end portion being defined as a starting point, preparing an outer frame including an annularly formed inner circumferential surface, arranging the lower die on an inner side of the outer frame, dropping a prescribed amount of molten glass droplet onto the lower die surface such that a surface of the molten glass droplet connects the outer edge end portion and a portion of the inner circumferential surface located above a position of the outer edge end portion to each other and the molten glass droplet does not wet-spread over the space forming surface, and pressurizing and molding the molten glass droplet.

A process deciding method in a method of manufacturing an optical element by heating and press-molding an optical material to mold the optical element using a molding die on which a release film is formed, includes a basicity degree identifying process in which a degree of basicity of the optical material is identified; and a removing process determining process of determining whether to perform one or both of first removing process in which an oxidizing substance is removed and a second removing process in which a basic substance is removed from at least one of a surface of the optical material and a surface of the release film by comparing the degree of basicity of the optical material identified in the basicity degree identifying process with a predetermined reference value, before press-molding the optical material.