A preform sterilization method that sequentially performs: a step in which disinfectant is caused to adhere to a resin preform (1) and microbes attached to the preform (1) are sterilized by gasifying the disinfectant and spraying this gas (G) from a nozzle (6) towards the traveling preform (1)； and a step in which hot air (P) is blown on to the preform (1) the disinfectant adhered to the preform (1) is activated the microbes attached to the preform (1) are sterilized and the disinfectant adhered to the preform (1) is removed from the preform (1). As a result disinfectant is not brought inside a blow molding machine.
