PURPOSE: To lessen fluctuation of the transmitted force from a control lever to a transmission lever of an electromagnetic part by accomplishing engagement of the two levers by the use of a mechanism which does not sink the transmission force.

CONSTITUTION: A roller 101 is caulked to a control lever 63 rotatably by a pin 102, other points remaining the same as any conventional arrangement. The motions of the roller 101 are also the same as conventional, provided that it generates rolling frictions to smoothen transmission of the force. If the roller 101 is arranged in this manner as a mechanism not reducing the transmission force, the influence of friction force upon the load transmission from the control lever 63 to transmission lever 34 can be reduced to ignorable level. This permits accomplishment of a remotely controllable circuit breaker with stable operation, wherein the transmission force is with minor fluctuation an the wear is less.