A method for cleaning a hot-wall type film formation apparatus having a batch processing system with industrially high mass productivity is provided. In the method, a carbon film deposited on an inner wall or the like of a reaction chamber of the apparatus is removed efficiently in a short time. To remove the carbon film deposited on the inner wall of the reaction chamber by a thermal CVD method, the reaction chamber is heated at a temperature higher than or equal to 700° C. and lower than or equal to 800° C., and oxygen is introduced into the reaction chamber.