Provided is a device identifying method for identifying an electronic device including an actual operation circuit operating at a time of actual operation of the electronic device and a test circuit provided with a plurality of test elements and operating at a time of testing of the electronic device, the device identifying method including: a property measuring step of measuring electric properties respectively of the plurality of test elements; an identification information storing step of storing the electric properties respectively of the plurality of test elements, as identification information of the electronic device; an identification information obtaining step of measuring, in an attempt to identify a target electronic device, electronic properties of a plurality of test elements included in the target electronic device, thereby obtaining identification information of the target electronic device; and a matching step of comparing the identification information obtained in the identification information obtaining step and the identification information stored in the identification information storing step, and judging that, when there is matching in identification information, the target electronic device whose identification information is obtained in the identification information obtaining step is the electronic device whose identification information is stored in the identification information storing step.