Abstract: Disclosed therein is a sterilizer for dental contaminants, which can prevent contamination occurring by the surface or a discharge hole of a cuspidor and a discharge hole of a suction mounted on a side of a dental unit chair used to spit out contaminants, such as blood or pus, remaining in a patient's mouth during a dental treatment. The sterilizer includes: a lid having a size as large as to cover an entrance portion of the cuspidor; an ultraviolet lamp mounted on the inner surface of the bottom of the lid; an opening and closing means connected to the lid for opening and closing the lid; and a control part for opening and closing the lid through the opening and closing means and controlling the turning on and off of the ultraviolet lamp.