PURPOSE: To obtain the recording medium excellent in the magnetic characteristics, by separating film through the immersion to water, after the vacuum deposition of alkail metal on the film and forming the ferromagnetic thin film layer on the substrate vapor-deposited with the copper.

CONSTITUTION: Under vacuum, the alkail metal or alkail earth metal is vapor- deposited on the plastic film to form the metal film and the copper substrate is formed by the vapor deposition of copper 1W20μm thick. After the ferromagnetic thin film layer on the copper substrate through the vapor deposition of specified ferromagnetic material, it is immersed in water, then the metal film formed on the film is dissolved as alkali hydroxide and the film can easily be peeled off from the copper substrate. With this method, the ferromagnetic thin film layer excellent in the surface smoothness is formed and the magnetic characteristics of recording medium can be increased.