PURPOSE: To maintain initial good basic performances including S/N, reproduced waveform, drop-out, etc. for a long period of time by disposing a polymerized film contg. aspherical pulverous particles on a high-polymer film and providing a thin ferromagnetic metallic film as a magnetic recording layer thereon.
CONSTITUTION: The glow discharge of styrene vapor is induced in a high-fre quency electric fleid while PE terephthalate is run and the polymerized film 2 of styrene is formed while the approximately hexagonal planar pulverous particle 3 are formed by evaporating Co therein. The film is subjected to diago nal vapor deposition of Co-Ni vapor flow 18 in the oxygen partial pressure while the film is run along a cooling can 16 in succession of the formation of the polymerized film to form magnetic recording layer 4. The film is there after taken up by a take-up shaft 8. The inside of a vacuum vessel 6 is restored to the atmospheric pressure upon completion of the longitudinal treatment. An alcohol soln. prepd. by dissolving a stearic acid is coated as a lubricating film by a coating machine and is dried to form a stearic acid film. The film is thereafter slit.