There is provided an inertia sensor with low noise and high sensitivity. The inertia sensor captures a physical quantity as a change of electrostatic capacitance and detects the physical quantity based on a servo voltage generating electrostatic force that cancels the change of the electrostatic capacitance. The inertia sensor includes a detection capacitor unit that captures the physical quantity as the change of the electrostatic capacitance and a servo capacitor unit to which the servo voltage is applied. Here, the detection capacitor unit and the servo capacitor unit are connected mechanically through an insulation material.