A method of sterilizing a bottle includes steps of: sterilizing bacteria adhering to a preform (1) made of resin by gasifying a sterilizer, discharging a sterilized gas (G) from a nozzle (6) toward a preform, now traveling, so as to adhere to the preform (1)； activating the sterilizer adhering to the preform by blasting hot air (P) to the preform； sterilizing the bacteria adhering to the preform, and removing the sterilizer adhering to the preform (1)； heating the preform to a temperature suitable for blow-molding treatment； and blow-molding the preform within a mold (4) to mold the preform into a bottle (2), wherein the above steps are performed sequentially in order. According to the above-mentioned steps, the sterilizer does not enter a blow-molding machine.
