To secure uniform wettability of a heat transfer plate face of a plate-type evaporator in starting operation and the like.

In this absorption type refrigerating device comprising a generator 1 heating an absorption dilute solution, a condenser 3 for condensing and liquefying a refrigerant vapor supplied from the generator 1, the evaporator 4 evaporating the refrigerant liquid supplied from the condenser 3, an absorber 5 spraying the absorption concentrated solution supplied from the generator 4 and absorbing the refrigerant vapor, and a solution pump 7 supplying the absorption dilute solution absorbing the refrigerant vapor to the generator 4; and evaporating the refrigerant of the evaporator transiently without circulating it, when the wettability of the heat transfer plate face of the evaporator 4 is degraded in starting operation and the like, the absorption dilute solution of a prescribed amount or more is supplied onto the heat transfer plate face of the evaporator 4 from the solution pump 7 for a prescribed time, and then a state is switched to a state of supplying only the refrigerant from the condenser 3, thus the wettability on the heat transfer plate face of the evaporator 4 can be secured.