Molds for press molding an optical element of glass are disclosed. Proposed are: (1) A mold contains oxygen at the interface between a mold base of the mold and a carbon film formed at least on the molding surface of the mold base with an oxygen amount of 0-10 atom % and with the interface of a width of 0-500 .ANG., (2) a mold subjected to carbon ion injection at least on the molding surface of the mold base, and (3) a mold subjected to ion injection during or after formation of a carbon film at least on the molding surface of the mold base material.