PURPOSE: To prepare a replica by sticking an acetyl cellulose film whose one face is dissolved with a methyl acetate to an observation surface in such a manner that said face contacts with the observation surface, holding the same for several minutes, then stripping the film and depositing copper by evaporation on the surface of the film corresponding to the dissolved surface thereof.

CONSTITUTION: The observation surface of an object to be observed of the degree of deterioration is buffed to a specular surface and thereafter the surface is cleaned and dried then etched with an etching soln. such as niter. The film which consists of the acetyl cellulose having about 0.03W0.04mm thickness of which one face is dissolved with the methyl acetate is stuck to the etched observation surface in such a manner that the dissolved surface contacts with the observation surface. After the film is held for several minutes, the film is stripped away and the copper is vacuum-deposited on the resulted transfer surface of the film. The replica for electron microscopic observation having the extremely high resolution to satisfactorily reflect microdefects is obtd. according to the above-mentioned method for forming the replica.