A combustion-type exhaust gas treatment apparatus is used to treat a harmful exhaust gas by combustion to render the gas harmless. The treatment apparatus includes a combustion treatment section, a cooling section, and a washing section. The combustion treatment section includes an exhaust-gas treatment combustor, a body made from metal and having a roughened inner surface, and a water-film formation mechanism adapted to form a water film on the inner surface of the body. The combustion treatment of the exhaust gas is performed in the body.