A current cut-off device for high-voltage DC current, of the type including: - a main line between a primary point and a secondary point, with an intermediate point in the main line between the primary point and the secondary point; - a primary diversion member (18, 180) interposed in the main line between the primary point and the intermediate point, the diversion member having at least an on-state, in which it conducts an electric current between the primary point and the intermediate point, and at least a diversion state, in which it opposes at least partly a passage of an electric current between the primary point and the intermediate point; - a primary surge protector electrically arranged in parallel with the primary diversion member (18, 180), between the primary point and the intermediate point; - a secondary mechanical switch interposed in the main line between the intermediate point and the secondary point, the secondary switch having an open state and a closed state; - a main resonator including at least a main inductance and a main capacitance electrically in series between a first terminal and a second terminal of the main resonator, the second terminal being electrically linked to the secondary point of the main line; - a main oscillation switch; - a main surge protector, electrically arranged in parallel at least with the main capacitance of the main resonator; characterized in that the main oscillation switch includes a three-terminal changeover switch comprising: - a direct terminal electrically linked to the primary point of the main line; - a inverting terminal electrically linked to the intermediate point of the main line; - an output terminal electrically linked to the first terminal of the main resonator; and able to switch at least between the three following states: - a direct state in which the output terminal is only linked to the direct terminal; - an inverting state in which the output terminal is only linked to the inverting terminal; and - an isolated state in which the output terminal is electrically isolated from the direct terminal and from the inverting terminal. - a main line between a primary point and a secondary point, with an intermediate point in the main line between the primary point and the secondary point; - a primary diversion member (18, 180) interposed in the main line between the primary point and the intermediate point, the diversion member having at least an on-state, in which it conducts an electric current between the primary point and the intermediate point, and at least a diversion state, in which it opposes at least partly a passage of an electric current between the primary point and the intermediate point; - a primary surge protector electrically arranged in parallel with the primary diversion member (18, 180), between the primary point and the intermediate point; - a secondary mechanical switch interposed in the main line between the intermediate point and the secondary point, the secondary switch having an open state and a closed state; - a main resonator including at least a main inductance and a main capacitance electrically in series between a first terminal and a second terminal of the main resonator, the second terminal being electrically linked to the secondary point of the main line; - a main oscillation switch; - a main surge protector, electrically arranged in parallel at least with the main capacitance of the main resonator; characterized in that the main oscillation switch includes a three-terminal changeover switch comprising: - a direct terminal electrically linked to the primary point of the main line; - a inverting terminal electrically linked to the intermediate point of the main line; - an output terminal electrically linked to the first terminal of the main resonator; - a direct terminal electrically linked to the primary point of the main line; - a inverting terminal electrically linked to the intermediate point of the main line; - an output terminal electrically linked to the first terminal of the main resonator; and able to switch at least between the three following states: - a direct state in which the output terminal is only linked to the direct terminal; - an inverting state in which the output terminal is only linked to the inverting terminal; and - an isolated state in which the output terminal is electrically isolated from the direct terminal and from the inverting terminal. - a direct state in which the output terminal is only linked to the direct terminal; - an inverting state in which the output terminal is only linked to the inverting terminal; and - an isolated state in which the output terminal is electrically isolated from the direct terminal and from the inverting terminal.