A waterproof connector comprises an inner housing made of synthesis resin, which accommodates a connection terminal; an outer housing made of synthesis resin, which surrounds the inner housing inserted in an insertion port with a predetermined space portion therebetween, the outer housing having an insertion port in its block wall, the insertion port being for inserting the inner housing, and an enter port provided in its tip end; and a sealing member inserted in the space portion, wherein a holding projection extending from the sealing member to the block wall is provided, a through hold inserting the holding projection therein is provided in the block wall, and the holding projection is inserted in the through hole. In such a constitution, thermoplastic resin covers at least an exposed portion of the holding projection, which is exposed from the through hole, from the outside of the block wall.