Electrical junction box

Provided is an electrical junction box in which a printed circuit board is accommodated in a case so as to configure an internal circuit, the electrical junction box having a new structure that can achieve downsizing/densification of the electrical junction box by configuring the internal circuit with a high space efficiency and simplifying routing of electric cables of connectors. As the internal circuit, a printed circuit board stack (16) is used in which a first printed circuit board (18) and a second printed circuit board (20) are arranged so as to face each other. A power supply input connector (70) that is to be mounted to a front wall-side connector mounting portion (53) provided on a front wall (47) of a case (15) is connectable to the first printed circuit board (18), whereas an output connector (80) that is to be mounted to a rear wall-side connector mounting portion (55) provided on a rear wall (48) of the case (15) is connectable to the second printed circuit board (20).