To provide a distribution board and an OA tap which can grasp service condition or the like of power, and a power monitoring system provided with them.

This distribution board is provided with a breaker unit 2, which cuts off power supply, when power supply in the respective branch lines BS1-BS32 constituted by dividing a trunk line MS into a plurality of lines becomes excessive, sensor units 3 which detect service conditions by each branch lines BS1-BS32, and A/D conversion units 4 which convert analog signals outputted, corresponding to the detected results from the sensor units 3 to digital signals and output them to a prescribed communication line.