To provide a metal smearing reduction method of a deposition device for restricting scattering of a metal constituent into a processing container and coping with narrowing of a tolerance range of the amount of scattering.

In the metal smearing reduction method, the deposition device includes a cylindrical vertical type processing container capable of holding vacuum state, a holding member arranged in the processing container for holding each treating body maintained at two or more stages, and a heating device arranged at an outer perimeter of the processing container. The metal smearing reduction method includes a step (step 4) of cleaning the inner wall of the processing container and the surface of the holding member by using cleaning gas, and a step (step 1) of forming a silicon nitride film on the inner wall of the processing container and the surface of the holding member, which have been cleaned, in MLD method and coating the inner wall of the processing container and the surface of the holding member with the silicon nitride film.