Disclosed is a withdrawable-type circuit breaker, including a cradle, a main body disposed to be inserted into and withdrawn from the cradle by a transfer device, and an interlock device for restricting a withdrawal of the main body when the circuit breaker is in a connected state, wherein the interlock device includes a support part vertically disposed on a bottom surface of the main body, an interlock lever, having a sliding hole at one end thereof and a power transmission part at another end thereof, hinge-coupled at its medium portion to one end of the support part, and an interlock pin having one end inserted into and coupled to the sliding hole and another end up and downwardly movable and insertable to an interlock pin hole formed in a bottom surface of the cradle.