A radioactive fine particle manufacturing system, comprising: a radioactive gas generating apparatus for generating a natural radioactive noble gas, a fine particle generating apparatus for generating a non-radioactive fine particle, and a mixing chamber for mixing the natural radioactive noble gas generated by the radioactive gas generating apparatus and the non-radioactive fine particle generated by the fine particle generating apparatus, wherein said radioactive gas generating apparatus includes a radiation source unit that has a natural radiation source therein, whereby the apparatus is configured to feed externally acquired air to the radiation source unit, mix the air and the natural radioactive noble gas generated from the natural radiation source, and feed the same to said mixing chamber, said fine particle generating apparatus includes a fine particle generator for generating a fine particle and a particle discriminator for discriminating a fine particle having a predetermined particle size, whereby the apparatus is configured to discriminate a non-radioactive fine particle having a predetermined particle size from the non-radioactive fine particle generated by the fine particle generator by using the particle discriminator and feed the same to said mixing chamber, and said mixing chamber is configured to attach a progeny nuclide converted by radioactive decay from the natural radioactive noble gas fed from said radioactive gas generating apparatus to the non-radioactive fine particle having a predetermined particle size fed from said fine particle generating apparatus to generate a radioactive fine particle having a predetermined particle size. a radioactive gas generating apparatus for generating a natural radioactive noble gas, a fine particle generating apparatus for generating a non-radioactive fine particle, and a mixing chamber for mixing the natural radioactive noble gas generated by the radioactive gas generating apparatus and the non-radioactive fine particle generated by the fine particle generating apparatus, wherein said radioactive gas generating apparatus includes a radiation source unit that has a natural radiation source therein, whereby the apparatus is configured to feed externally acquired air to the radiation source unit, mix the air and the natural radioactive noble gas generated from the natural radiation source, and feed the same to said mixing chamber, said fine particle generating apparatus includes a fine particle generator for generating a fine particle and a particle discriminator for discriminating a fine particle having a predetermined particle size, whereby the apparatus is configured to discriminate a non-radioactive fine particle having a predetermined particle size from the non-radioactive fine particle generated by the fine particle generator by using the particle discriminator and feed the same to said mixing chamber, and said mixing chamber is configured to attach a progeny nuclide converted by radioactive decay from the natural radioactive noble gas fed from said radioactive gas generating apparatus to the non-radioactive fine particle having a predetermined particle size fed from said fine particle generating apparatus to generate a radioactive fine particle having a predetermined particle size.