In a waterproof connector, a mat seal and a rear grid are attached to a rear side of a connector housing. These mat seal and rear grid include terminal insertion openings and electric wire insertion openings, respectively, which communicate with terminal receiving chambers. Wire tubes are fitted to electric wires to which large female terminals are crimped, and are brought into elastically intimate contact with inner walls of large terminal insertion openings of the mat seal. Moreover, each of the wire tubes includes a protruding portion that protrudes rearward from the large terminal insertion opening of the mat seal and is located in the large electric wire insertion opening.