To provide an apply method by which a production time per piece of a casting is short and a cost is low.

This apply method is performed on the basis, in which a treatment agent is applied on surfaces 3a, 4a of a mold wall in a mold 2 during shifting a next casting cycle after completing at one time a casting cycle and taking out the casting from the mold 2. At the treatment agent, mold lubricant containing no water is used. In the casting cycle repeatedly performed while an interval between prescribed casting cycles, a process for applying the treatment agent to the whole surfaces 3a, 4a of the mold wall is performed after passing through a process in which the surfaces 3a, 4a of the mold wall are made to reach a prescribed temperature. In an interval between the other casting cycles, a process for applying the treatment agent to a part of the surfaces 3a, 4a of the mold wall is performed after passing through a process in which the surfaces 3a, 4a of the mold wall are made to reach the prescribed temperature, or only a process in which the surfaces 3a, 4a of the mold wall are made to reach the prescribed temperature is performed.