To allow uniform and efficient sterilization of facilities selected from clean rooms, cell processing centers for human use (CPCs), medical-supply-manufacturing facilities, animal-rearing facilities (SPF animals), biohazard rooms, food processing facilities, and medical facilities, where walls, floors, ceilings, device surfaces, and spaces, including equipment interiors, can be sterilized while minimizing effects such as corrosion and using the smallest amount of chemical agent as possible, and whereby sterilization can be carried out without problems with residual toxicity and without the need for wiping operations subsequent to sterilization. In addition, an operator can initiate, monitor, and control sterilization from outside the sterilization zone and thus respond to unexpected circumstances such as damage to a sprayer during a sterilization operation. Moreover, a suitable sterilization environment can be produced and maintained automatically, and reliable sterilization can be carried out by a remote operator along with a main controller located at a distance that allows control.