An electrical junction box comprising: a casing configured to be mounted in a vehicle; a start electrical component housed in the casing in a first space (S1) thereof and to which a current is supplied at least at a start of the vehicle configured to control supply of current to a vehicle electrical component for starting the vehicle, the start electrical component including an electrical component case and a terminal portion , the terminal portion being housed in the electrical component case and having a contact (FC, MC); an operational electrical component housed in the casing in a second space (S2) thereof and to which a current is supplied at least during an operation of the vehicle; and a partition heat shield wall disposed between the start electrical component and the operational electrical component ; the electrical junction box further comprises: a circuit board housed in the casing, on which the start electrical component and the operational electrical component are mounted, the circuit board having a circuit pattern connected to the terminal portion ; a plate member housed in the casing, disposed such that at least the start electrical component is disposed between the plate member and the circuit board ; wherein the plate member is a second circuit board having a circuit pattern connected to the circuit pattern of the circuit board ; and the electrical junction box further comprises a second partition heat shield wall disposed between the start electrical component and the second circuit board . a casing configured to be mounted in a vehicle; a start electrical component housed in the casing in a first space (S1) thereof and to which a current is supplied at least at a start of the vehicle configured to control supply of current to a vehicle electrical component for starting the vehicle, the start electrical component including an electrical component case and a terminal portion , the terminal portion being housed in the electrical component case and having a contact (FC, MC); an operational electrical component housed in the casing in a second space (S2) thereof and to which a current is supplied at least during an operation of the vehicle; and a partition heat shield wall disposed between the start electrical component and the operational electrical component ; the electrical junction box further comprises: a circuit board housed in the casing, on which the start electrical component and the operational electrical component are mounted, the circuit board having a circuit pattern connected to the terminal portion ; a plate member housed in the casing, disposed such that at least the start electrical component is disposed between the plate member and the circuit board ; wherein the plate member is a second circuit board having a circuit pattern connected to the circuit pattern of the circuit board ; and the electrical junction box further comprises a second partition heat shield wall disposed between the start electrical component and the second circuit board . a circuit board housed in the casing, on which the start electrical component and the operational electrical component are mounted, the circuit board having a circuit pattern connected to the terminal portion ; a plate member housed in the casing, disposed such that at least the start electrical component is disposed between the plate member and the circuit board ; wherein the plate member is a second circuit board having a circuit pattern connected to the circuit pattern of the circuit board ; and the electrical junction box further comprises a second partition heat shield wall disposed between the start electrical component and the second circuit board . <EOS>