A backup cooling device intended for a hot isostatic press, the press comprising a compression chamber, a tank containing a gas and a first gas flow circuit for the gas to flow between the gas tank and the compression chamber. The backup cooling device comprises a tank containing a coolant equipped with a first heat exchanger for exchanging heat between the gas and the coolant, a coolant flow circuit forming a closed loop including the tank and a cooling circuit arranged around the compression chamber, a second gas flow circuit for the gas, extending from a connecting valve connecting it to the first gas flow circuit, and including the first heat exchanger, a control module (CMD) suitable for controlling the connecting valve so as to open it in the event of a malfunction of the hot isostatic press, and otherwise to close it.