An elastically supported electrode substrate for detecting unbalanced mass of a resonant gyroscope includes an outer frame and an inner structure. A connection part configured to be connected to an anchor of a resonator is arranged at the center of the inner structure, and electrodes are distributed on the inner structure. The inner structure is connected inside the outer frame through elastic beams, and the inner structure has torsional and/or translational resonant modes inside the outer frame. The resonant frequency of the inner structure approaches resonant frequency of an operating mode of the resonator. Since the resonant frequency of the elastically supported electrode substrate approaches the resonant frequency of the operating mode of the resonator, the vibration displacement induced by the unbalanced mass of the elastically supported electrode substrate can be significantly magnified to improve the detection sensitivity.