Abstract: A viscosity modifier is thermally stable and can provide an excellent viscosity-increasing effect and/or an anti-sagging effect, and is used by the addition to a paint, a coating agent, a painting agent, a flux, an adhesive material, and a sealing material that are produced/used under high temperature conditions. A film-forming agent contains the viscosity modifier including a polyamide component that contains a polyamide compound from a C2-10 aliphatic and/or C6-10 aromatic primary diamine and a C12-36 polybasic acid and/or a C12-30 unsubstituted or hydroxy-substituted aliphatic monocarboxylic acid. The film-forming agent contains the viscosity modifier and a film-forming component and is at least any one selected from a paint, a coating material, a painting material, a flux, an adhesive material, and a sealing material.