Abstract: The present invention relates to a circuit breaker comprising at least a pair of electrical contactors formed of conductors and contacts secured to the conductors for opening or closing an electric circuit in a container, light absorbers having opposed surfaces disposed oppositely to each other from both sides of an arc produced between the contacts at the isolating time, a thermal absorber disposed oppositely to the openings of the opposed surfaces of the light absorbers except the moving trace portion of the electrical contactors, the light absorbers being formed of a composite material having one or more of fiber, net and porous material having more than 35% of apparent porosity selected from composite materials having inorganic series, organic series and composites of the inorganic series and the organic series, and the thermal absorber being formed of a composite material having one or more of an assembly of fine metal wires, porous metals, and a metal plate having a number of pores.