PURPOSE: To form a uniform carbon coating film on a small body by heating the small body suspended in a flow of a gas not reacting with the body to a prescribed temp., introducing starting material for forming a carbon film into the flow and thermally decomposing the starting material.

CONSTITUTION: A small body is suspended in a flow of a gas not reacting with the body, this system contg. the small body is heated to a prescribed temp. and starting material for forming a carbon film is introduced into the flow to form a carbon coating film on the small body.