PURPOSE: To obtain an ultrasonic coordinate input device in which the fluctuation of propagation time can be suppressed by placing film made of resin on the plane of a propagation body, performing a coordinate instruction operation on the film, and adhering or crimping a film enclosure member on the film.

CONSTITUTION: Such structure is employed that the upper plane of a vibrationproofing member 4 stretched in the neighborhood of the propagation body 3 is adhered with PET film 30 with an adhesive 31, and the PET film 30 can be adhered by dead weight on the plane of the propagation body 3. Coordinate input is performed on the PET film 30. An ultrasonic signal applied to the propagation body 3 via the PET film 30 is propagated through the propagation body 3 in concentric circle shape from under an indicated point, and arrives at a sensor 2. Since the PET film 30 is not adhered with the propagation body 3 with the adhesive and also, appropriate coarseness exists on the surface of the PET film 30, acoustic coupling between them can be completely neglected at a part other than the indicated point.