PURPOSE: To detect the position where a metallic inside member is present through a nonmetallic outside member, by providing a metallic member detection display device subjected to flashing control by the change in the outputs from both of a nonmetallic member detection comparator and a metal member detector.

CONSTITUTION: As preparation for detecting a metallic inside member, a switch SW 1 is turned ON in such a state that a nonmetal/metal member detector 24 is brought into contact with the surface of a nonmetallic outside member on which a nonmetallic inside member and the metallic inside member are not present to set proper applying voltage to a nonmetallic member detection sensor 3. Next, when the detector 24 is moved to the position where the nonmetallic inside member is present, the electrostatic capacity of the sensor 3 gradually increases to become a detection state. When a metal detection switch SW 2 is turned ON in this state, since a metallic member detection sensor 4 does not approach the metallic inside member, the oscillation intensity of an oscillation circuit 22 is strong and a transistor TR 5 is turned ON and a metal detection lamp L2 does not light. Next, when the detector 24 is moved to the position where the metallic inside member is present, the oscillation intensity of the circuit 22 becomes weak and the transistor TR 5 is turned OFF and the lamp L2 lights.