A rare earth thin-film magnet of a Nd—Fe—B film deposited on a Si substrate, wherein, when the film thickness of the rare earth thin film is 70 μm or less, the Nd content satisfies the conditional expression of 0.15≤Nd/(Nd+Fe)≤0.25 in terms of an atomic ratio; when the film thickness of the rare earth thin film is 70 μm to 115 μm (but excluding 70 μm), the Nd content satisfies the conditional expression of 0.18≤Nd/(Nd+Fe)≤0.25 in terms of an atomic ratio; and when the film thickness of the rare earth thin film is 115 μm to 160 μm (but excluding 115 μm), the Nd content satisfies the conditional expression of 0.20≤Nd/(Nd+Fe)≤0.25 in terms of an atomic ratio. An object of the present invention is to provide a rare earth thin-film magnet having a maximum film thickness of 160 μm and which is free from film separation and substrate fracture, and a method of producing such a rare earth thin-film magnet by which the thin film can be stably deposited.