This document relates to a conductivity measurement method of thin metal films at microwave and millimeter-wave frequencies. This method has been developed to evaluate the conductivityof a metal foil used for adhering to a substrate or the interfacial conductivity of a metal layer formed on a dielectric substrate. It uses higher-order modes of a balanced-type circular disk resonator and provides broadband conductivity measurements by using a single resonator. In comparison with the conventional method described in IEC 61788-7, this method has the following characteristics: " the value of the conductivity 5Øß of a metal foil can be measured accurately and non-destructively; " the value of the interfacial conductivity 5Øß of a metal layer on a dielectric substrate can be measured accurately and non-destructively; " this method presents broadband measurements by using higher-order modes by one resonator; " this method is applicable for the measurements on the following condition: frequency: 10 GHz d"5ØSÜd" 170 GHz; 22 conductivity: 105 S/m d"5Øßd" 108 S/m.