Abstract: A thermocouple for use in an apparatus for manufacturing a semiconductor device having two metal wires, each composed of a different material, being connected at one end. A first insulator extends a first length from the connected end of the metal wires and electrically insulates a portion of one of the metal wires. A second insulator, having a brittleness factor less than that of the first insulator, extends a second length from the first insulator along the same metal wire. The lifetime of the thermocouple can be lengthened and productivity of the semiconductor device can be enhanced.