Harmonic drive gearing is not researched so much, and the characteristic of load transmission has not been explained. Therefore, the characteristic of load transmission in the harmonic drive gearing is hoped for the improvement of reliability and durability by clarification. In the present study, the measurement of the strain was enabled by using a comparatively large-scale harmonic drive gearing. As a result, a useful result for the clarification of the characteristic of load transmission, stress concentration position such as specification and affected of torque, was obtained.