To restrain generation of a leak current, and to restrain influence of external noise in a probe guard.

This probe guard is formed as a structure for arranging guard wires 6, 16 and 26 via an insulating layer around force wires 7, 17 and 27 in a probe needle 2, a connecting terminal 3, and a signal conductor pattern for constituting the probe guard, and is also formed as a structure for arranging GND wires 5, 15 and 25 via the insulating layer around these guard wires 6, 16 and 26. An external circuit is connected to the probe guard having such a structure. When performing tentative measurement, these guard wires 6, 16 and 26 are put in the same electric potential as the force wires 7, 17 and 27. The GND wires 5, 15 and 25 are put in earth electric potential. Thus, generation of the leak current and influence of the external noise can be restrained at tentative measurement time.