A waterproof harness connector that is simple, highly reliable, and can branch a wire. An inner holder is inserted into an outer holder from an opening, and then, joints of wire terminals, where seal members are attached to wires, are inserted into wire terminal holding holes of the inner holder through wire terminal insertion openings of the outer holder. When a pin terminal is inserted into pin terminal insertion hole of the inner holder, the pin terminal penetrates tubular contacts of the joints, which are placed in the holding hole, to electrically connect the wire terminals to each other. After that, a waterproof member is fixed to an opening to make the inside of the outer holder a waterproof structure.