A connector (10) includes a housing (30) with a terminal accommodating portion (31) into which a plurality of differently dimensioned terminals (20) are to be accommodated, and a retainer (60) retains the terminals (20) by being inserted through a side surface of the housing (30). The retainer (60) is moved laterally by operating an operating portion (63) and is held at a partial locking position and a full locking position by locking pieces (65) of the retainer (60) that engage locked portions (44) of the housing (30). The terminals (20) include medium terminals (20M) locked by medium locking lances (56) fit into an escaping portion (68) between the operating portion (63) and the locking pieces (65) in the retainer (60). The escaping portion (68) includes a reinforcement (69) for preventing deformation of the escaping portion (68).