An example of the present invention is a micromechanical device including, a substrate in which a signal line is provided, a micromachine which is mounted on the substrate, is formed of a conductive material into a beam-like shape, is elastically deformed by a function of an electric field in such a manner that the beam-like part moves closer to or apart from the signal line, and changes the electric characteristics concomitantly with the deformation, a deformation restraint section constituted of a material having a higher viscosity coefficient than the conductive material, provided on the opposite side of the micromachine to the signal line, for restraining deformation of the micromachine in a direction in which the micromachine is separated from the signal line, and a sealing body provided on the principal surface of the substrate, for covering the micromachine with a hollow section located therebetween.