There is provided a method of connecting electric wires in which connecting strength is improved, and at the same time, dispersion of the connecting strength can be depressed. The method of connecting electric wires includes a step for removing coatings of a plurality of electric wires 51 thereby to expose conductors 52, a step for holding at least two places of a plurality of the electric wires 51, a step for twisting the conductors together while keeping a distance between the two holding places constant, and a step for welding the conductors by ultrasonic welding.