The molding die set includes: a first molding die having a first molding chase, a cavity piece, supported by the first molding chase, movably supported by the first molding chase and enclosing the cavity piece; a second molding die having a second molding chase, a work supporting section biased and supported by the second molding chase and on which a work will be mounted, and a center insert located adjacent to the work supporting section; and a pot being provided to one of the first molding die and the second molding die, the pot feeding resin for molding the work. The second molding die has a thickness adjusting mechanism, which makes the work supporting section absorb thickness variation of the work and brings the work into contact with the movable clamper when the work is clamped with the movable clamper of the first molding die.