A pair of piezoelectric substrates, the length of which is shorter than the length of one side in the longitudinal direction of the operation panel or the supporting board, is respectively fixed to one side from the diagonal position along the longitudinal direction. At the time of detecting an inputting operation, a drive voltage is applied and the entire operation panel or the supporting board is vibrated. Even when the four corners of the operation panel or the supporting board are supported by the housing for accommodating the tablet apparatus or supported by the display device so that the vibration of the four corners is restricted, since either of the pair of piezoelectric substrates, which becomes a vibration source, a feeling of inputting operation can be transmitted to an operator by the vibration, the amplitude of which is not less than a predetermined value, irrespective of the inputting operation position.
