A pivot supporting structure for a circuit breaker and a circuit breaker. The pivot supporting structure includes: a supporting body having a supporting hole for receiving and pivotally supporting a pivot pin connected to an actuating mechanism of the circuit breaker, wherein at least one strain gauge are mounted to the supporting body for sensing the force acting on the pivot supporting structure by the actuating mechanism. This pivot supporting structure can accurately sense the characteristic force applied, such that the contact force and mechanical characteristics of the circuit breaker can be on-line monitored.