Abstract: An external operation handle device is used for a circuit breaker for switching a locker handle to ON and OFF positions. The handle device includes a main body casing for the circuit breaker, a mount base held on the main body casing, a rotary handle grip mounted on the mount base for turning the locker handle to the ON and OFF positions and having a connecting shaft, and an assist mechanism for moving the handle grip to a TRIP indication position upon tripping operation of the circuit breaker. The assist mechanism is interposed between the mount base and the handle grip, and includes a cam with a cam face, fixed on the mount base, a cam follower linking with the handle grip slidably along an axial direction and opposing the cam face of the cam, and an urging spring for pushing the cam follower against the cam face.