The present invention provides a female terminal fitting (20) to be crimped onto a wire comprising a core (12) formed by joining a plurality of wire strands (11) together, the terminal fitting being provided with: a bottom plate section (22) upon which the core (12) is to be placed; and a pair of barrel pieces (25L, 25R) that are interconnected to the bottom plate section (22) so as to wrap around the core (12) placed on the bottom plate section (22), said barrel pieces to be crimped onto the core (12). Thin sections (27) are formed on the butt portions of the barrel pieces (25L, 25R), and the thin sections (27) deform when the crimping pieces (25L, 25R) are crimped onto the core (12), resulting in the formation of corner sections (30). Since the thin sections (27) preferentially deform upon crimping and corner sections (30) are formed therefrom, the gaps formed at the butt portions of the barrel pieces (25L, 25R) can be made smaller in comparison to when there are no thin sections (27).