A wire harness for a vehicle seat is disposed in the vehicle seat and electrically connects electric parts to one another. The wire harness includes a flat circuit branch and a flat circuit body. The flat circuit body has one end connected to the circuit branch while the other end is connected to various electrical parts. The circuit branch also includes a sheet of branch seat or several sheets of branch seats that are selectively laminated to one another so that an electronic circuit corresponding to the specification or grade of the vehicle seat can be constituted.