There is provided a sterilizing apparatus which is capable of sterilizing articles, such as test tubes, flasks, beakers, scalpels, forceps and so on, with high efficiency in a short time. The sterilizing apparatus includes a sterilizing gas generator 42 that supplies sterilizing gas into a chamber 4. The sterilizing gas generator 42 atomizes a sterilizer solution (oxygenated water) by means of an ultrasonic vibrator 46. The sterilizing apparatus further includes an ultraviolet generator (ultraviolet lamp 50) that irradiates gas in the chamber 4 with an ultraviolet ray. The sterilizing apparatus further includes a door 14 for blocking an opening 2A of the chamber 4 in a free-opening/closing manner and a locking device 52 for prohibiting the door 14 from being opened. The sterilizing apparatus further includes a controller 60 for controlling the locking device 52 to prevent the door 14 from being opened from start of the sterilization process to end of the decomposition process.