A direct-current circuit breaker that creates a current zero point by superimposing a resonance current on a direct current flowing along a direct-current line and interrupts the direct current at the current zero point, the direct-current circuit breaker comprising: a breaker that is inserted into the direct-current line and becomes a path for the direct current when in a steady state; a resonance circuit that is connected in parallel with the breaker and superimposes a resonance current on the direct current after the breaker is opened, characterised in that it further comprises: a first disconnector that is connected at one end to a first connection point of the breaker and the resonance circuit and that forms a path for the direct current together with the breaker when in a steady state; and a second disconnector that is connected at one end to a second connection point of the breaker and the resonance circuit and that forms a path for the direct current together with the breaker and the first disconnector when in a steady state, wherein the resonance circuit includes a series circuit that includes a capacitor and a reactor and generates the resonance current, a charging resistor that is used for charging the capacitor with a direct-current potential of the direct-current line when in a steady state, a high-speed switch that is connected in series with the series circuit on the capacitor side and superimposes the resonance current on the direct current after the breaker is opened, and an arrester that is connected at one end to the first connection point and is connected at another end to a connection point of the capacitor and the reactor and that limits a current flowing into the capacitor from the direct-current line. a breaker that is inserted into the direct-current line and becomes a path for the direct current when in a steady state; a resonance circuit that is connected in parallel with the breaker and superimposes a resonance current on the direct current after the breaker is opened, characterised in that it further comprises: a first disconnector that is connected at one end to a first connection point of the breaker and the resonance circuit and that forms a path for the direct current together with the breaker when in a steady state; and a second disconnector that is connected at one end to a second connection point of the breaker and the resonance circuit and that forms a path for the direct current together with the breaker and the first disconnector when in a steady state, wherein the resonance circuit includes a first disconnector that is connected at one end to a first connection point of the breaker and the resonance circuit and that forms a path for the direct current together with the breaker when in a steady state; and a second disconnector that is connected at one end to a second connection point of the breaker and the resonance circuit and that forms a path for the direct current together with the breaker and the first disconnector when in a steady state, wherein the resonance circuit includes a series circuit that includes a capacitor and a reactor and generates the resonance current, a charging resistor that is used for charging the capacitor with a direct-current potential of the direct-current line when in a steady state, a high-speed switch that is connected in series with the series circuit on the capacitor side and superimposes the resonance current on the direct current after the breaker is opened, and an arrester that is connected at one end to the first connection point and is connected at another end to a connection point of the capacitor and the reactor and that limits a current flowing into the capacitor from the direct-current line.