A circuit breaker is disclosed, which has a resistor interposed in an arc contact to make a small breaking current flow, to facilitate breaking a fault current and to facilitate insulation recovery after breaking the fault current so that a breaking performance can be ultimately enhanced. A cylinder is filled with an arc-extinguishing gas. A fixed main contact is formed in the cylinder. A movable main contact is connected to the fixed main contact to form a first current path and then is separated from the fixed main contact for breaking a fault current at the time of detecting the fault current. A fixed arc contact is formed in the cylinder and has a resistor interposed between a body and a tip of the fixed ac contact for reducing the fault current. A movable arc contact is connected to the fixed arc contact to form a second current path so that the movable arc contact is in contact with the resistor of the fixed arc contact and then is separated from the fixed arc contact for reducing the fault current at the time of detecting the fault current.
