Disclosed is a vacuum circuit breaker. As a plurality of components of main circuit units are integrally formed as one module by molding using epoxy, the main circuit units are easily fabricated, and assembly errors are prevented. Since the main circuit units are arranged to be symmetrical to each other based on a driving unit, an insulation distance between a switchgear and the main circuit units can be obtained without increasing a size of the switchgear. This may allow the main circuit units to be easily arranged at the right side or at the left side according to an installation state of the switchgear.