To solve a problem that a method and a device for effectively preventing inflammation and explosion when a refrigerant gas leaks, when the combustible refrigerant gas is used in a refrigerating cycle, have not been provided.

In this residual gas recovering method and device of the refrigerating cycle using the combustible refrigerant gas, a pipe for recovering the refrigerant gas in emergency is connected to a pipe of the combustible refrigerant gas, and the recovering pipe is connected to a vacuum container for recovering the gas, so that the residual gas is sucked and recovered by the vacuum container when the refrigerant gas leaks. The vacuum container is cooled by utilizing the refrigerant condensate liquid of which a temperature is lowered, of a low temperature-side refrigerating machine unit in a binary type refrigerating machine unit.