A method of connecting a flat cable having flat conductors arranged in parallel and covered with an insulating material to a connecting terminal, in which crimp pieces of the connecting terminal are pierced into a desired conductor of conductors of the flat cable, with a gap left between a substrate of the connecting terminal and the flat cable, and leading ends of the crimp pieces penetrating the flat cable are bent inwardly, while maintaining a contact position of the crimp pieces penetrating the conductor and the conductor unchanged. Also disclosed are an apparatus for embodying the connecting method and a method for determining a connecting state between the flat cable and the connecting terminal.