Abstract: Disclosed herein is a dental tool sterilizer, which sterilizes a dental tool to keep the dental tool sanitary and allows a dental tool that has been sterilized or is to be sterilized to be conveniently and easily put into and taken out of the sterilizer. The sterilizer includes a support body having a turntable on an upper portion thereof, a power button being provided at a predetermined position on the support body to control supply of power. A dental-tool protective casing is provided such that an open bottom thereof is placed on the upper portion of the support body, and has a door on a side thereof. A sterilizing means is provided in the casing and has an ultraviolet lamp that radiates ultraviolet rays. A dental-tool holding means is provided on the turntable in such a way as to rotate along with the turntable, and holds dental tools.