Realized is a shape of a grooved cam that maximizes break performance by appropriately setting an electrode operation, with a minimum weight increase. A gas circuit breaker includes a drive side electrode and a driven side electrode which are disposed to face each other in a sealed tank, the drive side electrode having a drive side main electrode and a drive side arcing contact, the driven side electrode having a driven side main electrode and a driven side arcing contact, the drive side arcing contact being connected to an operating device, and the driven side arcing contact being connected to a double motion mechanism portion, in which the double motion mechanism portion includes a drive side connection rod that receives driving force from the drive side electrode, a driven side connection rod that is connected to the driven side arcing contact, a lever that is bent to the operating device side around a rotation axis by causing the driven side connection rod to operate in an opposite direction with respect to an operation of the drive side connection rod, and a guide that defines operations of the drive side connection rod and the driven side connection rod.