To highly sensitively detect the number of materials or the amount of materials to be measured.
A material detecting device comprises at least a magnetic sensor element; a signal acquisition means for acquiring the signal outputted by the magnetic sensor; and a magnetic field applying means for applying the magnetic field to the magnetic sensor element. In this case, the magnetic sensor is provided with a magnetic film as a constituent element, the magnetic field applying means is a means for applying the magnetic field on the magnetic sensor in the magnetization difficulty direction, and the information acquisition means for acquiring the information indicating the variation of signal outputted by the magnetic sensor element at the time, when one or more of the presence/absence of the applied magnetic field, the magnitude and the direction of the applied magnetic field is changed.
Ishibashi Masayuki
Masaaki Ogata