A device for quick closing of an electric high-voltage circuit. A main spark gap is provided with a first and a second main electrode, and a triggering device. The triggering device includes an auxiliary electrode gap provided with a first and a second auxiliary electrode and is adapted, where necessary, to generate an arc in the auxiliary spark gap for igniting an arc in the main spark gap. Each auxiliary electrode is provided with a guide rail designed such that the arc, via the guide rails and under the influence of the generated inherent magnetic field, moves into the main spark gap. The two guide rails each have a length that is larger than the width of the auxiliary spark gap. The auxiliary electrodes are adapted so as to be protected from the effect of plasma formed in the main spark gap. A hermetic enclosure encloses the main spark gap and the auxiliary spark gap.