A member having high non-electrostatic properties and high hydrophilicity and preventing an adhesion of contaminants, a surface-treating process and an apparatus for the surface-treating process are provided.A surface-treatment apparatus comprises a water vapor-generating unit 1, a superheating unit 5 for superheating a water vapor to generate a superheated water vapor, and a processing unit 11 for spraying the superheated water vapor to a member 14 to be treated (a ceramic, a metal) or for exposing the member to the superheated water vapor. Treating the untreated member with a superheated water vapor having a temperature 300 to 1000° C., hydrophilicity and antistatic properties are imparted to the member. The untreated member may be a member (a window member) contacting with a processing space in a vapor phase surface process apparatus (e.g., a chamber) for the surface process of a substrate by a vapor phase method such as a PVD, a CVD, or a dry etching.