ELECTRICAL CONNECTION BOX

A first electrical connection box includes a housing, a holder () that is provided inside the housing, and holds an electrical component () to which a first wire () is to be electrically connected; and a terminal block () attached to the holder (). The terminal block () includes a terminal support base () attached to the holder (), and a busbar () supported on the terminal support base (). The busbar () includes a planar first connection surface (), and a planar second connection surface () to which a second wire () is to be electrically connected. Also, the first electrical connection box further includes a relay busbar () that is provided inside the housing, and includes a third connection surface () that is electrically connected to the first connection surface (), and a fourth connection surface () that is electrically connected to the electrical component ().