To simplify management of a process of sterilization of a filling nozzle.In a method for sterilizing a filling nozzle, hot water or a liquid chemical agent is fed to drink supply piping (7) that feeds a drink to a plurality of filling nozzles (2a) at the same time, the hot water or liquid chemical agent is discharged from all the filling nozzles (2a), a flow rate of the hot water or liquid chemical agent is detected at all the filling nozzles (2a), a representative temperature of the hot water or liquid chemical agent upstream or downstream of at least one filling nozzle is measured, and a sterilization process is ended when both the flow rate at each filling nozzle and the representative temperature reach respective target values.
