A current cut-off device for high-voltage direct current, includes: at least one primary mechanical switch placed in a main line between a primary point and a secondary point; a primary surge arrester arranged in parallel with the primary switch; and an oscillatory circuit arranged electrically in parallel with the primary switch and electrically in parallel with the primary surge arrester. The oscillation circuit includes, electrically in series, at least an inductance, a capacitance and an oscillation trigger. The device has, in the oscillation circuit, a controllable device for varying the resistance value inserted in series into the oscillation circuit.