There are provided a machine tool cooling system and cooling method which allow cost reduction by reducing the number of control valves, and in which opening/closing control is simple. The machine tool cooling system and cooling method include a hot oil tank 4 storing hot oil, a cold oil tank 5 storing cold oil, a first to third hot oil passages 9a to 9c and a first to third cold oil passages 10a to 10c, which supply the hot oil and the cold oil to a first to third heat generating portions 1 to 3, a hot oil return passage 11 returning the hot oil to the hot oil tank 4, a first to third supply control valves 16a to 16c interposed in the first to third cold oil passages 10a to 10c, and a valve controller 8 controlling opening/closing of the first to third supply control valves 16a to 16c so that the cold oil is supplied to the first to third heat generating portions 1 to 3 intermittently at different timings.