Provided is an electrical connection box that is equipped with a newly constructed dark current circuit connection/disconnection mechanism that can be used to change circuits of the dark current circuit connection/disconnection mechanism and improve versatility. A conduction member holder has a conduction member holding portion that extends spanning over a plurality of cavities that are provided in a case. A conduction member includes: a first conduction member that is connected to a connection terminal of a dark current circuit housed in one of the cavities; and a second conduction member that is connected simultaneously to the connection terminal of the dark current circuits housed in one of the cavities and a connection terminal of another circuit housed in another cavity. The first conduction member or the second conduction member that is selected according to a required circuit configuration is mounted in the conduction member holding portion.