<p>A magnetic thin film memory device having information recorded in a magnetic thin film thereof by the direction of magnetization, and adapted to reproduce the recorded information on the basis of the voltage generated as a result of the change of the magnetization direction due to the extraordinary Hall effect, magnetoresistance effect or the like. A magnetic thin film memory device in which a magnetic thin film is formed of ferrimagnetic substance having perpendicular magnetic anisotropy, and producing extraordinary Hall effect in the composition of RE rich and having the minimum saturation field which enables recording in a small magnetic field and is hard to be influenced by temperatures. <IMAGE></p>