Abstract: The present invention relates to a gas switch provided with a body case wherein a switching unit is installed and an arc-extinguishing gas such as sulfur hexafluoride (SF6) or the like is enclosed at a constant pressure, and an actuating mechanism for operating the switching unit. When a pressure of the arc-extinguishing gas comes lower than a predetermined value, a lock member is disposed to a working position whereat it engages with the actuating mechanism, the actuating mechanism is thus locked unoperatably, and a display member is ready for observing externally in accordance with a shift of the lock member. Operators then carry out works for maintenance and check of the gas switch as ensuring the state wherein a gas pressure drops in the body case and the actuating mechanism has been locked.