A sulfur hexafluoride isolating circuit-breaker comprises an SF.sub.6 -filled gastight case for each cell containing fixed contacts and arcing contacts, the poles are fixed to a common grounded metal bar capable of pivoting between two end walls of a drawer suitable for containing the poles, said bar shelters a control shaft for the poles and connected to a control box which is itself connected to said bar, the rotation of the bar providing the section-switch isolating function and rotating or translating said shaft driving the circuit breaking function.