It is an object to provide an insulating film having a very low dielectric constant and a great mechanical strength. Moreover, it is another object to provide a semiconductor device capable of reducing both a capacity between wiring layers and a capacity between wirings also in microfabrication and an increase in integration in the semiconductor device. In order to attain the objects, there is provided an inorganic insulating film comprising a porous structure having a skeletal structure in which a vacancy is arranged periodically and a large number of small holes are included.