PURPOSE: To provide a money detector capable of always performing feature extraction and money specification decision with prescribed accuracy even when external environment or an internal factor is changed.

CONSTITUTION: Plural winding parts 9, 10 are formed at prescribed interval, and coils which pass a coin to be detected are provided at the hollow parts of the winding parts 9, 10, and a self-excitation oscillation circuit which generates an oscillation signal by cooperation with the coil are provided. The frequency of the oscillation signal and the specific change part of amplitude according to the change of impedance and inductance of each annular coil can be extracted as feature by the function of an eddy current generated in the coin to be detected by a magnetic field being generated in the coil when the coin to be detected passes the hollow parts of the winding parts 9, 10 of the coils.