In this study, we have developed a new technique to make a submicron multiporous membrane of a polyamic acid, a precursor of the polyimide, by covering the surface of the cast polyamic acid with a membrane which can control the substitution speed of a solvent. On heat-treating this membrane, a highly heat-resistant polyimide multiporous membrane was obtained. The membrane structure depends on the concentration of the polyamic polymer solution. It is therefore possible to create an excellent heat-resistant and solvent-proof membrane which has a special structure for various applications.