A method of roducing gamma -Fe2O3 magnetic disk medium of continuous thin film is provided, in which a deposition source is deposited on an opposed Al-alloy substrate by means of a reactive vacuum deposition technique and the deposited film is thermally treated so as to be the magnetic disk medium. As the deposition source, a ferroalloy containing about 1 to 10 at.% Ti and about 0.5 to 5 at.% Co is employed.
