To provide a resistance measuring device not requiring a long time for the resistance measurement work of a tire and maintaining the accuracy of measurement to assure the electrical conductivity characteristics of the tire and a method thereof.An electrical resistance measuring device for tires 10 comprises first and second probes 2, 3 for measuring an electrical resistance value of a tire 5, wherein the first probes 2 abut on a plurality of portions in an outer peripheral surface of a tread part 6 and the second probe 3 abuts on a periphery of a center part of a tire 5, and thereby an electrical resistance value between the tread part 6 and the bead part 9 is measured.