A microstructure which forms a micromachine is formed by using a silicon wafer as a mainstream, conventionally. In view of this, the invention provides a manufacturing method of a micromachine in which a microstructure is formed over an insulating substrate.The invention provides a micromachine including a layer containing polycrystalline silicon which is crystallized by thermal crystallization or laser crystallization using a metal element and including a space over or under the layer. Such polycrystalline silicon can be formed over an insulating surface and has high strength, therefore, it can be used as a microstructure as well. As a result, a microstructure formed over an insulating substrate or a micromachine provided with a microstructure can be provided.