an impedance meter is not adversely affected by errors originating from changes in characteristics of measurement cables under measurement conditions such as in an environmental test wherein an element to be measured is remote and high and wide measurement frequencies are used . the voltage and the current of an element to be measured are measured to obtain its impedance and the like . a circuit configuration is provided wherein a cable for supplying a measurement signal to the element to be measured and for detecting the current flowing through the element to be measured is a triaxial cable and a cable for detecting the voltage is a coaxial cable , and wherein impedance matching is performed at the ends of the triaxial cable and the coaxial cable on the side of a measuring device and a balun is provided to float an ammeter on a coaxial cable connecting the ammeter - side end of the triaxial cable to the ammeter .