An improved method for better and safer endonasal sinus surgery by use of an operating microscope and a newly designed self-retaining retractor speculum has been developed. The advantages of this method are summarized as follows ; 1) The target site is clearly magnified and focused. 2) Both of the operator's hands are available for the surgery itself. 3) Complete removal of the entire diseased tissues is possible. 4) The risk for complications is reduced. 5) Better training opportunities for the trainees are possible. The results of the surgery appear to be superior enough to recommend.