An operating device for a gas circuit breaker includes an operating piston reciprocably movable between a first position and a second position, with the operating piston dividing an internal space of the operating cylinder into a first chamber and a second chamber. An exhaust port in the operating cylinder communicates with the first chamber when the operating piston is disposed near the second position, and the exhaust port communicates with the second chamber when the operating piston is remote from the second position. High-pressure air is introduced into the first chamber at the time of the breaking operation. An exhaust valve device discharges the air from the first chamber when the air pressure within the first chamber decreases below a predetermined level. The exhaust valve device includes a valve element having a pressure-receiving portion receiving the air pressure from the first chamber. The pressure-receiving portion is positioned so as to be out of contact with the operating piston when the operating piston is disposed at the first position.