ELECTRICAL CONNECTION BOX AND WIRE HARNESS

Flat surfaces (21a, 41a) out of two flat surfaces of each of flat electrical connection bodies (21A, 41) of a relay bus bar (20) and a bus bar (40) of an electronic component (30) are mating surfaces brought into contact with each other by a fixing structure (50). At least one of the flat electrical connection bodies (21A, 41) of the relay bus bar (20) and the bus bar (40) applies a reaction force accompanying the elastic deformation to the other flat electrical connection body, to which the one flat electrical connection body is to be connected, in a state in which the flat electrical connection body (41) of the bus bar (40) at an accommodation completion position in a housing (10) has not been connected to the relay bus bar (20). The housing (10) includes a receiving portion (10g) receiving a force applied to the flat electrical connection body (41) of the bus bar (40) from the flat electrical connection body (21A) of the relay bus bar (21).