This paper deals with the optical telemeter system of strain-gauge output in rotating object. Bridge circuit composed of strain-gauges is connected to an amplifier and the output of amplifier is A/D converted according to the control series generated by a one-chip micro-controller, and the A/D result of serial data series is fed to LED on rotating object and sent as the optical data series. The optical data series is received by PD on stationary head, and the serial PD output is converted to parallel datum and inputted to personal computer. Tensile force acting on the sensing plate based upon the centrifugal force due to the spindle rotation is measured by the strain-gauge and the optical telemeter system. Theoretical tensile force is calculated. It is confirmed that the measured force coincides well with the theoretical force. This system has the function of quick-input of known-strain.