An intermediate housing (10) has a fitting recess (12) in which ends (91) of intermediate terminals (90) are located. An inner housing (30A) is fit into the fitting recess (12) and has first terminal fittings (110A) connectable to the intermediate terminals (90). A retainer (130) is inserted into the inner housing (30A) to retain the terminal fittings (110A). An outer housing (50) is fit externally onto the fitting recess (12) and includes an outer peripheral wall (53) surrounding the inner housing (30A). A mounting portion (21) projects on the outer surface of the fitting recess (12). The outer peripheral wall (53) is recessed to form an escaping portion (61) into which the mounting portion (21). The retainer (130) includes a confirmation surface (133) exposed to the outside of the inner housing (30A) when being inserted into the inner housing (30A) and visually confirmed from outside through the escaping portion (61).