PURPOSE: To obtain a device having no harmful influence on the vibration characteristic of a thin plate by providing at least one arm member for connecting the thin plate to a first tubular vibration element in a path extending from the first tubular vibration element to the thin plate for supporting it.

CONSTITUTION: A second bar-like element 4 is disposed in a cavity of a first tubular vibration element 2, and it has the same resonance frequency as the first tubular vibration element 2, and is vibrated in the opposite phase in use. The first tubular vibration element 2 is fixed to a flexible thin plate 7. In a path extending from the first tubular vibration element 2 to a thin plate for supporting it, two arm members 10 connected to the thin plate 7 are disposed. The arrangement direction is the direction crossing a line for connecting an excitation system 8 and a vibration detecting system disposed on the thin plate 7. The vibration system is more rigid and stronger in the direction of being protected from overload and on the other hand, the vibration element and the thin plate 7 crossing each other to be operated are not influenced, and the vibration is excited in this direction and detected.