An acceleration sensor includes a detection device, an opposed electrode, and a top lid. The detection device includes an active layer, a base layer, an oxide layer disposed between the active layer and the base layer, a first insulating layer, a contact portion, and a self-check electrode. The first insulating layer is disposed on the active layer at a side opposite to the oxide layer and provided with a first opening. The contact portion is disposed on a part of the first insulating layer at a side opposite to the active layer and includes a first metal layer connected to the active layer through the first opening. The opposed electrode is disposed at a location opposing the self-check electrode, and the top lid supports the opposed electrode.