To lower a return temperature of hot water as much as possible when driving a single effect absorption refrigerator by hot water, and to improve the refrigeration performance of the absorption refrigerator.

The single effect absorption refrigerator provided with an evaporator 12, an absorber 14, a regenerator 16 and a condenser 18 and configured to make drive hot water pass though the regenerator and perform heat exchange between a thick absorption liquid flowing from the regenerator to the absorber and a thin absorption liquid flowing from the absorber to the regenerator through an inter-absorption-liquid heat exchanger N0 includes a first heat exchanger N1 for performing heat exchange between the thin absorption liquid existing immediately before entering the inter-absorption liquid heat exchanger N0 and drive hot water flowing out from the regenerator 16.