<p>To provide a method for manufacturing a wire harness in which it is possible to prevent a decrease in joint strength or to enhance the joint strength at a protector joint while achieving a configuration in which the joint does not protrude outwards. A sheet-shaped member (14) is wound around the outer peripheral surface of a predetermined portion of a cable bundle (12) of a wire harness (1), and both side sections (141, 142) of the sheet-shaped member (14) are overlapped on the outer peripheral surface of the predetermined portion of the cable bundle (12). At least a portion of the overlapped portion of the sheet-shaped member (14) is pressed and subjected to ultrasonic welding using a jig (5) and a pressing member (horn (6)) of an ultrasonic welder, the jig being installed between the outer peripheral surface of the predetermined portion of the cable bundle (12) and the inner peripheral surface of the overlapped portion (both side sections (141, 142)) of the sheet-shaped member (14). A protector (13) made from the sheet-shaped member (14) is thereby formed on the outer peripheral surface of the predetermined portion of the cable bundle (12).</p>
