Abstract: A metal mold cooling device capable of employing a cooling pipe having a small diameter insertable into a cooling hole having a small diameter, and capable of performing fine supply control of a cooling liquid to the metal mold for fine temperature control thereto. A cooling pipe is connected to a compressed air source through a pipe and a first change-over valve. Further, the pipe is connected to a branch pipe to which a second change-over valve is connected. A hermetic cooling liquid tank connected to a water source is connected to the second change-over valve. A third change-over valve is provided between the compressed air source and the cooling liquid tank so as to apply pneumatic pressure onto a surface of the cooling liquid in the cooling liquid tank. Since the cooling liquid tank is provided in addition to the water source, pneumatic pressure from the compressed air source can be utilized. The cooling liquid in the cooling liquid tank is compressed and is supplied to the cooling pipe.