An apparatus for sterilizing the inside of an article such as a PET bottle comprises a hot air supplying device (14) for supplying hot air to the inside of an article (1), and a mist generating device (33) for producing mists of a sterilizing agent. By mixing the mists produced by the mist generating device with the hot air supplied by the hot air supplying device and introducing the same to the inside of the article, the sterilizing agent mists can be introduced evenly to every corner in the inside of the article so as to obtain an even sterilizing effect. Furthermore, the sterilizing apparatus comprises an air rinsing device (56) for discharging the air including the mists inside the article by blowing in the sterilized air to the inside of the article, and a washing device (57) for supplying a washing agent to the inside of the article.
