PURPOSE: To form an electrically conductive plasma-polymerized film on a surface of an insulating specimen, by placing inorganic salts on a high-frequency electrode and a specimen on a ground electrode, introducing vapor of a 5-membered cyclic organic compound into a reactor and generating glow discharge between both electrodes.

CONSTITUTION: A ground electrode 3 and a high-frequency electrode 5 are disposed facing each other in a reactor 1. A specimen 4 is placed on a face of the ground electrode facing with the high-frequency electrode and inorganic salts 14 are attached as a doping agent on a surface opposite to said ground electrode. Vapor of a 5-membered cyclic organic compound is introduced from an external source into said reactor and ejected in the form of a shower from the inside of the high-frequency electrode toward the ground electrode 3. A high-frequency power source 10 is connected to the high-frequency electrode 5 and glow discharge is generated between said electrodes to form an electrically conductive plasma-polymerized film on a surface of the specimen 4.