A chlorine dioxide gas generator including a frame body which houses a first chemical tank which is filled with a first chemical containing chlorite, a second chemical tank which is filled with a second chemical containing acid, a reactor which causes a reaction between the first chemical containing chlorite and the second chemical containing acid, and a separation tank which separates a chlorine dioxide gas from a chlorine dioxide solution generated in the reactor, the chlorine dioxide gas generator being adapted to disinfect an enclosed space by means of the chlorine dioxide gas.
