The disclosure relates to a circuit-breaker for high-voltage applications including at least one making and breaking unit having a first contact and a second contact for forming an electrically conductive connection in a connection region, wherein the first contact has an outlet arranged distant to the connection region for insulating gas passing the connection region and through the first contact and wherein the first contact is movable along an axially extending switching axis of the circuit-breaker over a moving distance between a closed position where the electrically conductive connection is formed and an open position where the electrically conductive connection is separated; a gas compression cylinder that is motion-coupled to the first contact and which defines a cylinder volume for the insulating gas, wherein the cylinder volume is variable by means of a piston sliding in the gas compression cylinder when moving the first contact.