A circuit breaker controller (100, 100a, 100b) for an electric train mounted on each vehicle of the electric train together with a receiver for detecting a track antenna beacon installed at a predetermined position before and after a dead section, to control a circuit breaker provided between a power collector and a main circuit device by detecting the track antenna beacon by the receiver, the circuit breaker controller (100, 100a, 100b) comprising: a running-position calculation unit for calculating a current running position of the vehicle based on a speed of the electric train and kilometrage information; a track-antenna-beacon detector connected to the receiver for outputting a track-antenna-beacon detection signal indicating that the receiver has detected the track antenna beacon installed before the dead section in a traveling direction of the train; a circuit-breaker control-position calculation unit (22, 22a, 22b) connected to the track-antenna-beacon detector for calculating a circuit-breaker off-control position at which the circuit breaker is off-controlled, based on the track-antenna-beacon detection signal output from the track-antenna-beacon detector, the kilometrage information, and the speed of the electric train at a point in time at which the receiver detects the track antenna beacon installed before the dead section in the traveling direction; and wherein the circuit-breaker off-control position is determined so that circuit interruption is performed at a predetermined interruption position, the predetermined interruption position being an always invariable position with a predetermined distance before the entering position to the dead section, wherein the predetermined interruption position being predetermined before the circuit-breaker control position calculation unit calculates the circuit-breaker off-control position; a circuit breaker control unit for executing off-control of the circuit breaker at a point in time at which the running position and the circuit- breaker off-control position coincide with each other. a running-position calculation unit for calculating a current running position of the vehicle based on a speed of the electric train and kilometrage information; a track-antenna-beacon detector connected to the receiver for outputting a track-antenna-beacon detection signal indicating that the receiver has detected the track antenna beacon installed before the dead section in a traveling direction of the train; a circuit-breaker control-position calculation unit (22, 22a, 22b) connected to the track-antenna-beacon detector for calculating a circuit-breaker off-control position at which the circuit breaker is off-controlled, based on the track-antenna-beacon detection signal output from the track-antenna-beacon detector, the kilometrage information, and the speed of the electric train at a point in time at which the receiver detects the track antenna beacon installed before the dead section in the traveling direction; and wherein the circuit-breaker off-control position is determined so that circuit interruption is performed at a predetermined interruption position, the predetermined interruption position being an always invariable position with a predetermined distance before the entering position to the dead section, wherein the predetermined interruption position being predetermined before the circuit-breaker control position calculation unit calculates the circuit-breaker off-control position; a circuit breaker control unit for executing off-control of the circuit breaker at a point in time at which the running position and the circuit- breaker off-control position coincide with each other.