METAL DETECTION DEVICE

In order to provide a metal detection device capable of automatically and accurately determining whether a metal passing through an inspection region is a magnetic metal or a nonmagnetic metal, this metal detection device is provided with: a wave-detection unit (24) that performs quadrature detection of a differential detection signal (Sd) of magnetic field fluctuation in an inspection region (Z) caused by passage of a workpiece (W); and a determination unit (36) that has a first determination unit (36a) which detects, on the basis of both fluctuation components (X, Y) after the wave-detection, the presence/absence of a metal being mixed. The determination unit (36) has: a second determination unit (36b) that determines the phase by comparing sample signal phase data (33) acquired in advance from a detection signal of magnetic field fluctuation in the inspection region (Z) caused by passage of each of metal samples (Tp1, Tp2) among a plurality of metal samples, with signal phase data (theta n) acquired from t