An arc extinguishing device of a gas circuit breaker includes: an arc chamber in which an arc generated between a movable electrode and a fixed electrode is formed; a heat puffer chamber disposed so as to surround the arc chamber; a blow port in which the arc chamber communicates with the heat puffer chamber in the circumferential direction of the arc chamber; hydrogen absorbents which are disposed on an inner wall of a pressure chamber; an exhaust port which passes to the outside of an arc extinguishing chamber; and a hydrogen absorbent disposed at a position surrounding the movable electrode. Deterioration of insulation due to a product formed by decomposition of arc extinguishing gas by the arc during a contact opening operation can be suppressed.