A waterproof connector includes a first housing formed with a recess, and a sealing unit to be sandwiched between the first housing and a second housing fit into the recess, to thereby keep waterproofness between the first and second housings, the sealing unit including a locking ring for engaging the sealing unit to the recess at a predetermined position, a holder for preventing a terminal having been inserted into the first housing from being released out of the first housing, and a waterproof seal sandwiched between an outer surface of the locking ring and an inner surface of the recess.