ELECTRICAL CONNECTION BOX

An electrical connection box (1) includes an insulating connection box housing (2) and an insulating branch box housing (5). The insulating connection box housing (2) stores a conductive connection box bus bar (3) therein, and the insulating branch box housing (5) stores a conductive branch box bus bar (6) therein. The branch box housing (5) and the connection box housing (2) are stacked in a vertical direction (Z). The connection box bus bar (3) and the branch box bus bar (6) are electrically connected by bringing connection box bus bar tip portions (32b and 33b) of the connection box bus bar (3) into direct contact with branch box bus bar tip portions (61b and 62b) of the branch box bus bar (6) and by jointly fastening the tip portions using bus bar fastening members (81 and 82).