The displacement amount monitoring electrode structure according to the present invention is for maintaining the amplitude of the detection mass at a constant target amplitude even when the relative relationship between a fixed electrode and a movable electrode changes, and includes a fixed electrode and a movable electrode each having a comb-teeth shape including a base part and electrode fingers extending from the base part in a predetermined axis direction parallel to a substrate, the fixed electrode and the movable electrode facing each other such that the electrode fingers of the fixed electrode and the electrode fingers of the movable electrode are meshed together, the fixed electrode being fixed to the substrate and the movable electrode being able to be displaced in the predetermined axis direction, wherein the displacement amount monitoring electrode structure monitors a displacement amount of a detection mass to be driven at a target amplitude based on a change amount of a capacitance between the fixed electrode and the movable electrode, wherein a change sensitivity of the change amount of the capacitance with respect to a displacement amount of the movable electrode in the predetermined axis direction, becomes larger after the displacement of the movable electrode in the predetermined axis direction reaches a target displacement amount corresponding to the target amplitude of the detection mass, compared to before the displacement of the movable electrode reaches the target displacement amount.