A switch that more reliably prevents solvent permeation from the outside, and a manufacturing method thereof are provided. The switch includes a first molded resin molded integrally with a plurality of fixed contacts by insert molding, a movable member disposed above the first molded resin to bring the plurality of fixed contacts into and out of contact with each other, and a second molded resin molded so as to close a through hole of the first molded resin formed by a pin supporting the plurality of fixed contacts at a time of the insert molding.