A semiconductor structure provided with an insulation structure in a moving unit is manufactured easily. An optical scanning mirror (semiconductor structure) is formed by processing an SOI substrate consists of a first silicon layer, an oxide film and a second silicon layer. A moving unit, which is supported on a fixed frame through first hinges, is formed on the first silicon layer. The moving unit is divided into a plurality of regions by forming trenches (insulation structure). A supporting member formed of the oxide film and the second silicon layer is formed just below the trenches. The plurality of regions of the moving frame divided by the trenches are joined to the supporting member, so that the moving unit is swingable with the supporting member. Thereby, the supporting member is formed by simple etching processes, and thus, mechanical strength of the moving unit is ensured.