Abstract: A touch panel comprises a substrate 11 allowing acoustic wave to be propagated and a transducer 13a, mounted to this substrate, for transmitting or receiving the acoustic wave. A chamfered portion 16 is formed in the end face or the corner portion of the substrate 11 to make the acoustic wave turn around and be propagated from the front surface to the rear surface through the end face of the substrate 11. The acoustic wave propagated through the chamfered portion is received by the transducer 13a placed on the rear surface of the substrate 11. The radius (R) of the chamfered portion 16 of the substrate is 0.5 mm or more. This touch panel may prevent from forming raised portions on the front surface of the propagation medium, so that the touch panel may be enhanced in applicability to thin LCD monitors, and simplified in structure.