Abstract: The invention relates to a device (1) for massaging or treating the muscles of the back and neck of a patient, comprising a housing (2) in which a drive motor (3) drives an annular crank track (6) by means of a gearbox (4). A lift motion acting on a massage finger (8) is generated by means of a guide unit (7). The geometric dimensions of the annular crank track determine the constant amplitude or the constant stroke of the massage finger (8) or of the massage head (83) thereof. The massage finger (8) is thus displaced at a constant amplitude, while the frequency is changed in accordance with a controller (10). The massage device (1) according to the invention works extremely quietly. The special construction thereof allows the resonant frequency of each muscle to be achieved.