A cooling system for a low pressure casting device, which includes an upper mold provided with a core portion of a spark plug and an upper die, a lower mold provided with a mold portion of a combustion chamber and a lower die, and side molds, may include i) a coolant supply unit connected respectively to the core portion of the spark plug, the upper die, the mold portion of the combustion chamber, and the lower die through coolant supply lines, ii) a cooling air supply unit connected respectively to the side molds and the mold portion of the combustion chamber through air supply lines, and iii) a vacuum intake unit connected respectively to the core portion of the spark plug, the upper die, the mold portion of the combustion chamber, and the lower die through vacuum intake lines.