An object of the invention is to provide a MEMS device that is easy to set a cavity inner pressure to a desired value by utilizing normally-used MEMS device manufacturing processes and process materials without increase in the number of processes of manufacturing the MEMS device. In order to solve the problem, as a typical MEMS device of the present invention, a MEMS device having a cavity includes an insulating film containing hydrogen in vicinity of the cavity and a hydrogen barrier film covering the insulating film.