A metal detection apparatus comprises: a detection circuit unit (30) that detects a first variation component having a large influence of workpiece and a second variation component having a large influence of metal; a determination unit (40) that compares the two variation components to perform a metal determination process in the workpiece (W); and a detection condition adjustment unit (60) that adjusts detection conditions of both variation components. A foreign matter waveform storage unit (50) stores a test variation component accompanying temporal change due to metal influence is further provided. The detection condition adjustment unit sets a specific processing condition of detection processing in the detection circuit unit based on the first variation component based on the magnetic field variation signal at the time when the work W including no metal passes through the inspection zone Z and the second variation component constituted by the test variation component.