A connector (10) has a terminal fitting (17) press-fit into a terminal holding portion (18). The terminal fitting (17) has a wide rectangular cross-sectional shape and includes a lower surface (17A), two side surfaces (17B) standing upward from the opposite lateral edges of the lower surface (17A) and an upper surface (17C) connecting the upper edges of the side surfaces (17B). The terminal holding portion (18) includes two side walls (18B) that interfere with the side surfaces (17B), a bottom wall (18A) formed with lower interfering portions (18E) that interfere with non-touching parts (17D) of the lower surface portion (17A) not to be held in contact with a mating terminal fitting (21) and a ceiling wall (18C) formed with upper interfering portions (18D) that interfere with non-touching parts (17D) of the upper surface (17C) not to be held in contact with the mating terminal fitting (21).