A magneto-optical head assembly for a reflection type magneto-optical memory apparatus uses a laser beam for recording, retrieving, and erasing data on a recording medium comprised of a vertical, magnetic, and anisotropic thin film. The light beam emitted from the head assembly is guided to a fixed position on said recording medium. Included are a light detection apparatus for receiving a control signal, and a separate light detection apparatus for receiving a data signal. A beam splitter, to which has been applied a multicoated thin film dielectric body capable of increasing the Kerr rotation angle of the laser beam reflected from the recording medium, is positioned in the optical system through which the laser beam passes.