An electrical junction box has a switch connected between a first connection terminal and a second connection terminal to which a fuse is mounted, and a control circuit configured to perform opening/closing control of the switch, has a storage unit for storing a standard resistance value in an initial state of the fuse and an amount of change in a resistance value of the fuse over time, and detects a first terminal voltage at the first connection terminal and a second terminal voltage at the second connection terminal. The control circuit opens the switch at a time of startup based on a control signal, calculates the resistance value of the fuse, calculates a reference resistance value, determines whether the fuse is correct by comparing the calculated resistance value of the fuse with the calculated reference resistance value, and outputs a first error signal if the fuse is incorrect.