The wheel torque measuring system (abbr. WTMS) has been developed for evaluating the torque applied to each wheel of automotive vehicles under actual running conditions. WTMS is a novel type system in which the torque signal is transmitted by a high-performance and compact photo-telemetric coupling system. Within the torque measurement range of ±2.94 kN·m, the resolution of torque output is ±1 N·m so that torque can be measured with an extremely high degree of accuracy. Therefore, measurements can be taken from the high torque applied in the case of a quick accelerating test or a sudden braking test to the measurement of a low amount of torque such as running resistance of a vehicle.