A touch panel input device is provide with a panel capable of propagating surface acoustic waves and in which surface acoustic wave attenuation is caused by a object in contact with said panel. An emission circuit outputs a surface acoustic wave drive; and an emission transducer emits surface acoustic waves in the panel in accordance with the surface wave drive outputted from said emission circuit. A reception transducer receives surface acoustic waves in the panel and outputs a received acoustic signal. A reception circuit receives the received acoustic wave signal from the reception transducer to detect a position at which the received acoustic wave is attenuated as indicative of a position that the object contacts the panel. A controller controls the emission circuit and the reception circuit, and comprises a processor for computing a width of the contact by the object on the panel in accordance with a waveform detected by the reception circuit. A judging circuit distinguishes a type of object in contact based on the width obtained by the processor.