An electrical junction box includes a circuit structure and a casing in which the circuit structure is accommodated. The casing includes a case including a case-side peripheral wall portion that extends upright from a peripheral edge of a bottom plate portion, the case having an opening that opens to a lateral side, and accommodating the circuit structure inside, and a cover closing the opening of the case and including a cover-side peripheral wall portion that extends upright from a peripheral edge of a lid plate portion and covers a perimeter of the case-side peripheral wall portion. In a state in which the cover and the case are assembled, a protruding end of the cover-side peripheral wall portion extends to at least such a position that its protruding end is substantially flush with an outer surface of the bottom plate portion.