Provided herein is a cancer detection and treatment instrument comprising: a first conductive plate; a second conductive plate which is opposed to the first conductive plate and has a first opening; a first signal line disposed between the first conductive plate and the second conductive plate; a first contact member of which one end is exposed through the first opening and of which the other end is connected to the first signal line; a dielectric portion filled between the first and second conductive plates and the first signal line; and a conductive layer surrounding both side surfaces and a front end surface of the dielectric portion which are exposed. Therefore, it is possible to accurately detect cancer by the use of the ultrahigh-frequency signal and to treat a diseased portion without damaging tissues around the diseased portion.