A chemically adsorbed multilayer film is formed through the process of replacing a halogen atom on the surface of a chemically adsorbed film with an alkaline metal or changing the halogen atom to a Grignard group by Grignard reaction. This manufacturing method does not disrupt the molecules of the chemically adsorbed film, is easy to perform, low in cost and is safe. After replacing the halogen (for example, Br) on the surface of the film with an alkaline metal such as Li, a condensation reaction including a dealkalihalide reaction is promoted by contacting the chemically adsorbed film with an adsorbent, such as a chemical adsorbent--containing a halosilane group at one end of a molecule--dissolved in a nonaqueous solvent. A chemically adsorbed multilayer film is then formed by reacting the chemically adsorbed film with chemical absorption composition and with water after removing unreacted adsorbents using a nonaqueous solution.