A housing (10) made of synthetic resin is formed with a pair of interference surfaces (17A, 17B) symmetrical with respect to a virtual axis of symmetry (S) and oblique to the virtual axis of symmetry (S) and receiving portions (16) spaced apart from the interference surfaces (17A, 17B) in a direction of the virtual axis of symmetry (S). The upper and lower covers (21A, 21B) of wire (20) are formed with interference portions (27) that come into contact with only parts of the pair of interference surfaces (17A, 17B), and contact portions (26) that come into contact with the receiving portions (16). The interference portions (27) contact the interference surfaces (17A, 17B) and plastically deform when the housing (10) and the wire cover (20) are connected and the receiving portions (16) and the contact portions (26) are held in contact.