PROBLEM TO BE SOLVED: To provide a sterilizer of x-ray imaging apparatus for the oral cavity in dentistry.SOLUTION: A sterilizer 10 of x-ray imaging apparatus for the oral cavity in dentistry comprises a sterilization chamber A including a first holding part 13 for holding a grip of the x-ray imaging apparatus for the oral cavity in dentistry and a sterilization lamp 12. The lower part of the sterilization chamber A comprises a second holding part 19 including a roll holder for holding a waterproof cover sheet 60 in a roll state, composed of a plurality of waterproof covers 61 for covering an imaging part which holds imaging components of the x-ray imaging apparatus for the oral cavity in dentistry.COPYRIGHT: (C)2015,JPO&INPIT【課題】歯科用口腔内X線撮影装置の消毒用の殺菌装置を提供する。【解決手段】歯科用口腔内X線撮影装置の殺菌装置10は、歯科用口腔内X線撮影装置のグリップを保持する第1保持部13と、殺菌灯12とを含む殺菌室Aを備える。殺菌室Aの下部に、歯科用口腔内X線撮影装置における撮影部材を保持する撮像部を覆う防水カバー61を複数並べた防水カバーシート60をロール状に保持するロールホルダーを含む第2保持部19を備える。【選択図】図9