It is aimed to reliably restrict the insertion of a terminal fitting in an improper posture. A connector includes terminal fittings 40 to be inserted into terminal accommodating chambers (13) of a housing (10) successively through through holes (61) of a rubber plug holder (60) and sealing holes (51) of a one-piece rubber plug (50), restricting projections (44) projecting from the outer surfaces of the terminal fittings (40), wires (46) passing through the through holes (61) in a state where the terminal fittings (40) are inserted in the terminal accommodating chambers (13), and restricting portions (17) provided to be located in the terminal accommodating chambers (13) and configured to restrict inserting movements of the terminal fittings (40) by interfering with the restricting projections (44) halfway through when the terminal fittings (40) are inserted in an improper posture into the terminal accommodating chambers (13).