PURPOSE: To constitute the title composition so that precipitation is not generated even if the title composition is stored for a long period of time and the same does not peeled off from a mold at the time of centrifugal compaction of concrete also, by making use of a mixture of specific oil and alkali by dispersing the same into a solvent.

CONSTITUTION: A mixture constituted of montan wax, bran wax, rosin and tall oil is dispersed into water or a mixture of water and an organic solvent. A water-soluble organic solvent such as water, methanol, ethanol, propanol and acetone are suitable for a solvent. After a composition as mentioned above has been applied evenly to the inside of a mold frame with a brush or a spray, the same is left as it is and the solvent is volatilized. Then a concrete mixture is cast into the mold frame. The concrete mixture is heated at 60W70°C by steam after the same has been left behind under the normal temperature for several hours. When the concrete mixture is removed from the mold after the concrete mixture has been cooled gradually by suspending the steam, a molded product of concrete can be produced. The composition is stable for a long period of time under the normal temperature, when the solvent applied to the mold frame is volatilized, a strong film is formed on the surface of a mold frame.