Abstract: Larger cavities (15, 16) for accommodating large terminals (6) are arranged at the opposite lateral sides of a housing (1), and small cavities (20) for accommodating small terminals (7) are arranged between the large cavities (15, 16). A retainer (4) is inserted laterally through a side surface of the housing (1). Lances (14) in the large cavities (16) at the trailing side with respect to an inserting direction of the retainer (4) are arranged on a passage route of the retainer (4), and hence are formed in a front holder (5) to be assembled after insertion of the retainer (4). Thus, the arrangement positions of the large cavities (16) are not restricted to the leading side with respect to the inserting direction of the retainer (4).