A vibration damping mechanism for use in a disc brake which can effectively suppress squeaks of the disc brake during braking. Vibrations of the rotor (1) are detected by a piezoelectric element (7-1) pressed against the back of the inner pad (2a). The detection signal is inputted in a control circuit (9). The control circuit (9) applies a control signal to another piezoelectric element (7-2) to produce oscillations having such a frequency that they can reduce the detection signal to zero. The oscillations produced by the piezoelectric element (7-2) are transmitted to the rotor (1) to cancel its vibrations. With this arrangement, signal components other than the rotor vibrations are scarcely contained in the detection signal, so that it is possible to produce oscillations that can cancel vibrations of the rotor (1) with high accuracy. As a result, the rotor vibrations and thus squeaks of the disc brake are effectively suppressed.