A low-noise and high-sensitivity inertial sensor is provided.On the assumption that a movable portion VU1 and a movable portion VU2 are formed in the same SOI layer, the movable portion VU1 and the movable portion VU2 are mechanically connected to each other by a mechanical coupling portion MCU even while these movable portions are electrically isolated from each other. Thereby, according to a sensor element SE in the invention, it is possible to further suppress a shift between the capacitance of a MEMS capacitor 1 and the capacitance of a MEMS capacitor 2.