An absorption chiller for obtaining a cold water, comprising: a cooling cycle having a regenerator , a condenser , an evaporator , and an absorber ; a cooling water pipe that extends from a cooling water inlet to a cooling water outlet via the absorber and the condenser , the cooling water inlet being configured to receive a cooling water from a cooling tower , and the cooling water outlet being configured to discharge the cooling water toward the cooling tower ; a heating medium pipe configured to supply a heating medium to the regenerator and to discharge the heating medium whose temperature is lowered in response to heating of a dilute solution in the regenerator ; a cooling water inlet shut-off valve (V2) provided on the cooling water inlet ; a cooling water outlet shut-off valve (V3) provided on the cooling water outlet ; a heating medium supply pipe (CP1) configured to supply the heating medium from the heating medium pipe to the cooling water pipe ; a cooling water discharge pipe (CP2) configured to discharge the cooling water from the cooling water pipe to the heating medium pipe ; a first control valve (CB1,CB2) provided on the heating medium supply pipe (CP1) and the cooling water discharge pipe (CP2), respectively; a cooling water temperature detector configured to detect a temperature of the cooling water in the cooling water pipe ; and a controller configured to cause the first control valve (CB1, CB2) to be opened and to cause the heating medium in the heating medium pipe to be introduced into the cooling water pipe , when the temperature detected by the cooling water temperature detector is equal to or lower than a predetermined temperature, in a wet lay-up state including a state in which the cooling water inlet shut-off valve (V2) and the cooling water outlet shut-off valve (V3) are closed and the cooling water pipe is filled with the cooling water. a cooling cycle having a regenerator , a condenser , an evaporator , and an absorber ; a cooling water pipe that extends from a cooling water inlet to a cooling water outlet via the absorber and the condenser , the cooling water inlet being configured to receive a cooling water from a cooling tower , and the cooling water outlet being configured to discharge the cooling water toward the cooling tower ; a heating medium pipe configured to supply a heating medium to the regenerator and to discharge the heating medium whose temperature is lowered in response to heating of a dilute solution in the regenerator ; a cooling water inlet shut-off valve (V2) provided on the cooling water inlet ; a cooling water outlet shut-off valve (V3) provided on the cooling water outlet ; a heating medium supply pipe (CP1) configured to supply the heating medium from the heating medium pipe to the cooling water pipe ; a cooling water discharge pipe (CP2) configured to discharge the cooling water from the cooling water pipe to the heating medium pipe ; a first control valve (CB1,CB2) provided on the heating medium supply pipe (CP1) and the cooling water discharge pipe (CP2), respectively; a cooling water temperature detector configured to detect a temperature of the cooling water in the cooling water pipe ; and a controller configured to cause the first control valve (CB1, CB2) to be opened and to cause the heating medium in the heating medium pipe to be introduced into the cooling water pipe , when the temperature detected by the cooling water temperature detector is equal to or lower than a predetermined temperature, in a wet lay-up state including a state in which the cooling water inlet shut-off valve (V2) and the cooling water outlet shut-off valve (V3) are closed and the cooling water pipe is filled with the cooling water. <EOS>