To provide a method for preparing patterning formation in a molecular order capable of being applied to an organic transistor or the like.

An organic monomolecular film is formed on a substrate and a pattern is formed on the monomolecular film by partially removing the monomolecular film by a tunnel current radiation using a scanning tunneling microscope probe as a means for giving external stimulus. A preparation method of the patterned monomolecular film is made to a main constitution.