Provided is an electrical junction box that enables suppression of entry of water even when the electrical junction box is installed in a vehicle in different orientations. Disclosed is an electrical junction box including a first case having an opening, a second case configured to cover the opening, and an accommodated component that includes a circuit assembly and is housed between the first case and the second case. The second case includes a peripheral wall formed by connecting a plurality of flat faces in a polygonal shape to cover an outer periphery of the first case adjacent to the opening. The first case includes water guard walls extending along at least two of the flat faces to cover a region not covered with the peripheral wall.