The present invention relates to an isolation mechanism of a controller for a direct current circuit breaker, which has a simple structure for isolation and connection manipulation. The isolation mechanism of a controller for a circuit breaker comprises a first connector that has a plurality of output terminals electrically connected to the controller and a plurality of input terminals detached from the output terminals for connecting an input electric power source; and a second connector that has a first connection position connected to the first connector and a second connection position rotated at 180° from the first connection position and connected to the first connector, and has a conductor wiring portion electrically connecting the output terminals with the input terminals at the first connection position and electrically disconnecting the output terminals from the input terminals at the second connection position.