Contact arc extinguishing device of circuit breaker

A contact arc-extinguishing device of a circuit breaker comprises a contact system and an arc-extinguishing chamber, and the contact system comprises a moving contact and a static contact; the arc extinguish chamber comprises a group of arc extinguish grid sheet groups which are arranged in a right-angle shape by a plurality of arc extinguish grid sheets; the static contact is connected with a static contact arc striking plate; the static contact arc striking plate extends to the lower end of the inverted-L-shaped arc extinguishing grid piece set, and the moving contact corresponds to the moving contact arc striking plate. The moving contact arc striking plate extends to the left end of the inverted L-shaped arc extinguishing grid sheet group; an air outlet channel is formed in the outer side of the inverted-L-shaped arc extinguishing grid piece group; the gas outlet channel is characterized in that the gas outlet channel is gradually increased from the left end of the inverted-L-shaped ...