To accurately grasp voltage setting.

A branch breaker includes: a casing provided with a plurality of connections 65-67 engageable with a plurality of conductive bars N, L1, L2 for supplying different levels of power respectively. The branch breaker 15 includes: switching knobs 61, 62 for setting a pair of connection terminals 63, 64 to be connected to the conduction bars N, L1, L2 to an arbitrary pair of connections among a plurality of the connections 65-67. The branch breaker includes: a microswitch 72 that transmits an ON signal indicating a first state when the connection terminal 63 is set to the connection 65 among a plurality of the connections 65-67 by the switching knob 61, and transmits an OFF signal indicating a second state when the connection terminal 63 is not set to the connection 65 by the switching knob 61.