Abstract: Disclosed herein is a vacuum circuit breaker. In some embodiments, a vacuum circuit breaker includes a cradle having a rail which forms a travel route; a main body being movably mounted to the cradle and configured to be in a test position or in an operation position; a wheel traveling along the travel route and configured to move the main body to the test position or the operation position; an interlock plate provided in the main body so as to move together with the main body; and a ground interlock device restraining the movement of the main body by restraining the movement of the interlock plate when grounded.