To prevent emitted noise from being transmitted to a measuring cable and a handle part by supporting an antenna receiving emitted electromagnetic wave from an object to be measured with the handle part connected to the measuring cable at an optional angle.

A connector 12 connected to the end part of a coaxial (measuring) cable 10 is formed with posts 14a, 14b on the end part, and their end parts are respectively formed with ring-like supporting parts 16a, 16b. An antenna 18 receiving emitted electromagnetic wave of an object to be measured is formed so that the circumference of a copper wire except both end parts is coated with insulating material 22, terminals 20a, 20b for connecting to the supporting parts 16a, 16b are formed on both end parts, and conductive grease is spread on the contact faces so as to prevent contact from being defective. The antenna 8 is rotated against the supporting parts 16a, 16b, and the shapes of the supporting parts 16a, 16b and the terminals 20a, 20b are set so as to obtain fixed frictional force to be fixed at an optional angle. Hereby, because the angle of the antenna 8 can be optionally set, emitted noise can be prevented from being transmitted to the coaxial cable 10 and the connector 12.