A decontamination system for decontaminating, with respect to one or more rooms targeted to be decontaminated, an inside of each room targeted to be decontaminated, by using decontamination gas, the decontamination system having compressed air-generating means for generating compression air and decontamination solution-supplying means for supplying decontamination solution which is a source of generation of decontamination gas, the decontamination system comprising: mixed gas-liquid adjusters (31, 32, 33, 34, 35) to adjust, with respect to each room targeted to be decontaminated, decontamination mixed gas-liquid obtained by respectively mixing the compression air and the decontamination solution; gas generators (41, 42, 43, 44, 45) to gasify the mixed gas-liquid to generate decontamination gas; air supplying pipes (11, 12, 13, 14, 15) which communicate from the compressed air-generating means up to the mixed gas-liquid adjusters; decontamination solution supplying pipes (21, 22, 23, 24, 25) which communicate from the decontamination solution-supplying means up to the mixed gas-liquid adjusters; and mixed gas-liquid supplying pipes (61, 62, 63, 64, 65) which communicate from the mixed gas-liquid adjusters up to gas generators, wherein the compressed air-generating means, the decontamination solution-supplying means, and the respective mixed gas-liquid adjusters are arranged at positions which are spaced from each room targeted to be decontaminated, and each of the gas generators is arranged near or in each of the rooms targeted to be decontaminated that corresponds thereto, and a conveyance distance of the mixed gas-liquid supplying pipe with respect to each room targeted to be decontaminated is thereby longer than a conveyance distance of each of the decontamination solution supplying pipes that corresponds thereto. mixed gas-liquid adjusters (31, 32, 33, 34, 35) to adjust, with respect to each room targeted to be decontaminated, decontamination mixed gas-liquid obtained by respectively mixing the compression air and the decontamination solution; gas generators (41, 42, 43, 44, 45) to gasify the mixed gas-liquid to generate decontamination gas; air supplying pipes (11, 12, 13, 14, 15) which communicate from the compressed air-generating means up to the mixed gas-liquid adjusters; decontamination solution supplying pipes (21, 22, 23, 24, 25) which communicate from the decontamination solution-supplying means up to the mixed gas-liquid adjusters; and mixed gas-liquid supplying pipes (61, 62, 63, 64, 65) which communicate from the mixed gas-liquid adjusters up to gas generators, wherein the compressed air-generating means, the decontamination solution-supplying means, and the respective mixed gas-liquid adjusters are arranged at positions which are spaced from each room targeted to be decontaminated, and each of the gas generators is arranged near or in each of the rooms targeted to be decontaminated that corresponds thereto, and a conveyance distance of the mixed gas-liquid supplying pipe with respect to each room targeted to be decontaminated is thereby longer than a conveyance distance of each of the decontamination solution supplying pipes that corresponds thereto.