WIRE CONNECTING METHOD AND WIRING HARNESS

[Technical Problem]An object of the present invention is to provide a wire connecting method and a wiring harness allowed to reduce the number of types of terminals for reducing cost by increasing the number of core wire sizes able to be crimped or press-connected with respect to one terminal. [Solution to Problem]Regarding covered wires 13, 14 of which core wire diameter is larger than the core wire diameter allowed to be crimped with a wire barrel 18, an ultrasonic processing in which while pressure is applied to a core wire 16, ultrasonic energy is applied to the core wire 16 is performed. Thereby, the core wire diameter is reduced to be allowed to be crimped to the wire barrel 18, and the core wire 16 of the covered wire 13, 14 is crimped or press-connected between a pair of crimping pieces 18B of the terminal 15. Regarding covered wires 11, 12 of which core wire diameter is allowed to be crimped to the wire barrel 18, the ultrasonic processing is not performed, and the core wire 16 of the covered wire 13, 14 is directly crimped between the pair of crimping pieces 18B of the terminal 15.