In the process of inserting a terminal fitting (20) into a cavity (11), a locking portion (16) is resiliently deformed along a partition wall (12) or an outer wall (13) due to the interference with the terminal fitting (20). Escaping recesses (17) are formed in surfaces of the partition walls (12) and the outer wall 13 facing the locking portions (16), whereby the widths of the locking portions (16) can be enlarged while defining clearances between the partition walls (12) and the locking portions (16) and clearances between the outer wall (13) and the locking portions (16). Thus, an area of engagement of each locking portion (16) with the terminal fitting (20) can be enlarged to improve a retaining function of the locking portion (16).