This paper describes an overload protection mechanism for a 6-axis force/torque sensor. It can limit the load applied to the force sensor by contacting a sole part with a top plate placed on the force sensor. Specifically, compression springs are arranged between the force sensor and the top plate, and the springs are precompressed. When more loads than the preload are applied to the top plate, the top plate touches the sole part by compressing the springs, and it is possible to prevent the 6-axis force/torque sensor from being over-loaded. Verification of the proposed mechanism is conducted through experiments with a human-carrying biped robot, WL-16RV.