Abstract: A retainer (40) has first securing portions (48) for securing terminal fittings (30) by entering deformation-permitting spaces (17) to prevent the resilient deformation of locks (13) and second securing portions (50) for securing the terminal fittings (30) by directly engaging the terminal fittings (30). Thus, even if one of the first securing portions (48) and the second securing portions (50) are narrowed to make a connector smaller, the terminal fittings (30) can be locked securely by the other securing portions and an insufficient insertion can be detected.