A micro structure and an electric circuit included in a micro electro mechanical device are manufactured over the same insulating surface in the same step. In the micro electro mechanical device, an electric circuit including a transistor and a micro structure are integrated over a substrate having an insulating surface. The micro structure includes a structural layer having the same stacked-layer structure as a layered product of a gate insulating layer of the transistor and a semiconductor layer provided over the gate insulating layer. That is, the structural layer includes layers formed of the same insulating film as the gate insulating layer and the same semiconductor film as the semiconductor layer of the transistor. Further, the micro structure is manufactured by using each of conductive layers used for a gate electrode, a source electrode, and a drain electrode of the transistor as a sacrificial layer.