A medical instrument is provided in which a wireless IC tag is fixed to a first or second body, such that at least part of the wireless IC tag is positioned more frontward than a front end of a first ring and a front end of a second ring and more backward than a support. A winding axis of an inductor is orthogonal to the up-down direction and intersects the front-back direction so that electric, magnetic, or electromagnetic field coupling is established between a resonant circuit and a metal medical instrument. Moreover, the metal medical instrument either emits a transmission signal, which has a frequency equal to a predetermined resonant frequency and supplied from the resonant circuit, as an electromagnetic wave, or it receives a reception signal having a frequency equal to the predetermined resonant frequency as an electromagnetic wave, and supplies the reception signal to the resonant circuit.