Abstract: A temperature control system includes a first chiller, a first tank, a first tank bypass channel, a first mixing valve that adjusts a mixing ratio of a fluid flowing from the first tank into the first chiller to a fluid flowing from the first tank bypass channel into the first chiller, a second chiller, a second tank, a second tank bypass channel, a second mixing valve that adjusts a mixing ratio of a fluid flowing from the second tank into the second chiller to a fluid flowing from the second tank bypass channel into the second chiller, a first supply valve, a first return valve, a first on-off value, a second supply valve, a second return valve, a second on-off valve, and a controller that controls the valves.