To enable the treatment of infected chickens in a closed chicken farm at a low cost.

In the case that the farmed chickens are infected with infection such as bird influenza, etc., at the in or out of the chicken farm, this treating apparatus is constituted by driving a self-traveling conveying vehicle 1 into a place where the infected chickens live, opening the lid 2b of a treating vessel 2 loaded on the self-traveling conveying vehicle 1, housing the infected chickens in the vessel and closing the lid so as to cause euthanasia of the infected chickens by introducing exhaust gas exhausted from the engine of the self-traveling conveying vehicle 1 into the treating vessel 2.