To provide a surface modifying method for extending the life of a crucible made of graphite to be used for aluminum vapor deposition and silicon refining, and an inexpensive crucible made of graphite.

A carbon source/silicon powder dispersion formed by dispersing a carbon source and silicon powder in a solvent is applied at least on the surface to touch a metal melt to form a mixed layer of the carbon source/silicon powder. The mixed layer of the carbon source/silicon powder is baked in a vacuum or under an inert gas atmosphere to carbonize the carbon source, and further subjected to a reactive baking treatment at an elevated temperature of 1,300°C or higher in a vacuum or under an atmosphere containing a nitrogen source to form a film of silicon carbide or a mixed film of silicon carbide and silicon nitride.