PURPOSE: To obtain finely pulverized carbon black in high yield, by adding a light oil to a stock oil for the production of carbon black, heating the mixture under pressure to suppress the evaporation of both components and spraying into a gas stream in a reaction furnace.

CONSTITUTION: A stock oil for the production of carbon black is added with a light oil in a furnace black reaction furnace and is heated at or above the boiling point of the light oil under the inner pressure of the reaction furnace while maintaining the pressure to a level to suppress the evaporation of the stock oil and the light oil. The heated mixture is sprayed into a high- temperature gas stream in the reaction furnace to obtain the objective carbon black.