A compact sensor device having stable sensor characteristics and the production method are provided. The sensor device is formed with a sensor substrate and a pair of package substrates bonded to both surface of the sensor substrate. The sensor substrate has a frame with an opening, a movable portion held in the opening to be movable relative to the frame, and a detecting portion for outputting an electric signal according to a positional displacement of the movable portion. Surface-activated regions are formed on the frame of the sensor substrate and the package substrates by use of an atomic beam, an ion beam or a plasma of an inert gas. By forming a direct bonding between the surface-activated regions of the sensor substrate and each of the package substrates at room temperature, it is possible to avoid inconvenience resulting from residual stress at the bonding portion.