Abstract: An object is to provide a beverage supply device which can cool cooling water in a water tank provided with a beverage cooling pipe by use of a cooling unit using a refrigerant having little influence on global environment, a beverage dispenser is provided with the beverage cooling pipe (syrup cooling pipe, diluting water cooling pipe, carbonated water cooling pipe) disposed in the water tank to store cooling water, the water tank being cooled by an evaporation pipe, the beverage dispenser passes syrup, diluting water, and carbonated water as beverage ingredients through the beverage cooling pipe to extract beverage, and the beverage dispenser comprises: a cooling unit in which a compressor, a radiator, a capillary tube, the evaporation pipe and the like are connected to one another via a pipe to constitute a refrigerant circuit and which is filled with carbon dioxide as the refrigerant.