Provided is an operation mechanism of a modulization breaker. A lever and a lock latch are respectively installed on a contact support in pivot mode. Contact locking state and separation unlocking state exist between the first hasp face on the lever and the second hasp face on the lock catch. The lever, the lock catch and the contact support cannot conduct relative free movement in the contact locking state, and the lever and the lock catch can rotate freely relative to the contact support in the separation unlocking state. A first connection structure of a movable contact and a pressure spring are installed on the contact support, one end of the spring is connected with the contact support, the other end of the spring is connected with the movable support, and the spring stores energy and provides contact pressure for the movable contact and a static contact which are in the closing state. The lock catch is provided with a limit piece installed and connected through a second connection structure, an elastic antenna on the limit piece is contacted and in sliding fit with the sliding face of an outer casing. The modulization breaker not only improves reliability and service life but also is low in volume, less in part and low in cost, thereby being suitable for large-scale automatic production.