The wire harness according to the present invention comprises electric wires each including a conductor. The electric wire is configured of a low-current electric wire used for a power source circuit, a high-current/ground electric wire used for a high-current power source circuit or a ground circuit and allowing a larger current than that of the low-current electric wire to flow, and a signal electric wire used for a signal circuit. The low-current electric wire and the high-current/ground electric wire are formed of an aluminum electric wire in which the conductor is made of aluminum or an aluminum alloy. The signal electric wire is formed of a copper electric wire in which the conductor is made of copper or a copper alloy.