A contact sensitive device (10) comprising a member (12) capable of supporting bending waves, a sensor (16) mounted on the member for measuring bending wave vibration in the member, the sensor (16) determining a first measured bending wave signal and a processor which calculates information relating to a contact on the member (12) from the measured bending wave signal, wherein, the surface of themember containing lifting type, so slipping the surface contact to supply the member with variable force in order to generate bending wave in the member.