Disclosed herein is an inertial sensor. There is provided an inertial sensor 100, including: a plate-like substrate layer 110, a mass body 130, a post 140, a support part 150 extending in the central direction of the mass body 130 from the post 140, and a detection unit 170 detecting the displacement of the displacement part 113. The inertial sensor adopts the support part 150 limiting the downward displacement of the mass body 130 to prevent the support portion of the mass body 130 from being damaged.