An apparatus for sterilizing and disinfecting a target space by spraying a chemical including alcohol includes a spray gun 4 to which a chemical container 7 containing a sterilizing and disinfecting chemical including alcohol is attachable, a gas cylinder 1 filled with a compressed carrier gas that does not react with alcohol, and a pressure reducing valve 2 for decompressing the carrier gas discharged in a vaporized state from the gas cylinder 1 to a predetermined pressure, and is constructed so that the pressure reducing valve 2 and the spray gun 4 are directly connected with a gas hose 3 and mounted on a common truck 5. The sterilizing and disinfecting apparatus can operate with a simple structure requiring no power supply, and is much lighter in weight compared to conventional apparatuses.