Abstract: The present invention discloses a gas cooling device and a reflow oven using thereof. The gas cooling device comprises a liquid cooling machine, a plurality condensers and a plurality of outer sleeves. The condensers are disposed in parallel and connected to the liquid cooling machine, in which two ends of all the condensers are separately connected with valves. The outer sleeves are sleeved out of the condensers and communicatively connected in order, in which the outer sleeves disposed at two ends are provided, respectively, with a gas inlet and a gas outlet and each of the condensers is provided with a water outlet. Each of the condensers is formed a circulation with the cooling device. Even though any of the condensers is detached, other condensers are able to continue operating as long as the valves disposed at the two ends of the detached condenser are closed.