Patent ID: 7663361

Claim:
A metal detection device for detecting metal contained in a test material based on a change of a magnetic field, which is detected by a reception coil, comprising a magnetic field generation means ( 2 ) for generating a magnetic field including a first frequency and a second frequency, which is different from said first frequency, by a transmission coil (L 1 ) on said test material that is moving and said reception coil ( 4 ) for detecting said change of said magnetic field when said test material is being moved, wherein: said magnetic field generation means has said transmission coil, a first capacitor (C 1 ), and a second capacitor (C 2 ); said transmission coil is electrically connected to said first capacitor and said second capacitor; and said magnetic field generation means further has a jointed portion ( 2 a ) that comprises a first tuning functional part ( 2 aa ) that connects said transmission coil and said first capacitor in response to said first frequency and tunes to said first frequency, and also comprises a second tuning functional part ( 2 ab ) that connects said transmission coil and said second capacitor in response to said second frequency and tunes to said second frequency.