ELECTRIC CONNECTION BOX

An electric connection box includes: the housing, or a plurality of communication connectors (the communication system connectors 54b, 55b, 56b) provided therein; a communication switch circuit (the switching hub functional unit 53), which is provided inside the housing, has a communication relay function and controls a communication path between the plurality of communication connectors; and a common power supply circuit (59), which is provided inside the housing and capable of supplying common power generated based on the power from the input side power supply line to a plurality of electric circuits including the communication switch circuit.