Overcurrent tripping sensitivity regulating device used for MCCB

The invention discloses an overcurrent tripping sensitivity regulating device used for a MCCB (Molded Case Circuit Breaker). The overcurrent tripping sensitivity regulating device has a simple structure and can regulate sensitivity according to different rated current in the MCCB. The overcurrent tripping sensitivity regulating device includes a lever which is rotatable and arranged to push a cross rod with a predetermined force for the purpose of pushing the cross rod in a direction opposite to a direction in which a double metal piece pushes the cross rod when overcurrents flow in the circuit; a replaceable sensitivity regulating spring having one end contacting with the lever and providing elastics to the lever to facilitate the lever to rotate in one direction, and used for determining the pressure of the lever; and a supporting component having a surface supporting the other end of the overcurrent tripping sensitivity regulating device and arranged to support the lever in a rotary manner.