PROBLEM TO BE SOLVED: To deodorize a room where a deceased person and/or an animal is left unattended. A method for deodorizing a room where a deceased person and/or an animal has been left unattended, which is a room after filth cleaning work for cleaning filth consisting of one or more selected from body fluid, feces, and urine, and a room after filth cleaning work. And an ozone fumigation operation for spraying ozone therein. [Selection diagram] None