Disclosed is an operated position detecting device for detecting a position in which an operation is performed and an electronic musical instrument using the detecting device, such as an electronic stringed instrument or an electronic keyboard instrument. Each of frets (2), with which conductive strings (1) are brought into contact, is formed of a two-layer structure of a conductive member (14) and a resistance member (13) provided on the conductive member (14). Voltage pulses are sequentially applied to either the conductive strings (1) or the conductive members (14) of the frets (2) and a voltage pulse is detected from a conductive member (14) or a string (1), thus detecting a position in which a string (1) is stopped against the fret (2).