An electric vehicle comprising: a main battery; a charging system electronic device including a battery charger and a 12V voltage transformer configured to charge a vehicle-mounted electric power supply that includes the main battery and the battery of low voltage system; an electrically powered system-based electronic device including a booster, an auxiliary machine and a power drive unit that includes an inverter configured to convert direct-current power of the main battery into alternating-current power, thereby driving a motor for travelling; a first high-voltage electric wire that connects the charging system electronic device and the electrically powered system-based electronic device to any one of the positive electrode side and the negative electrode side of the main battery; and a second high-voltage electric wire that connects the charging system electronic device and the electrically powered system-based electronic device to the other one of the positive electrode side and the negative electrode side of the main battery, wherein the booster is connected in series to the first and second high-voltage electric wires (13, 14) and the auxiliary machine and the electrically powered system-based electronic device are branch-connected to the first and second high-voltage electric wires (13, 14), and the electrically powered system-based electronic device and the charging system electronic device are electrically disposed in parallel to the main battery, and the electric vehicle further comprises: a first junction relay capable of isolating the first high-voltage electric wire; and a second junction relay capable of isolating the second high-voltage electric wire, the first junction relay is electrically disposed between the main battery and the charging system electronic device, and a first pre-charge relay that bypasses the first junction relay is electrically disposed in parallel with the first junction relay, and the second junction relay is electrically disposed between the charging system electronic device and the electrically powered system-based electronic device, characterized in that the charging system electronic device is electrically disposed between the main battery and the electrically powered system-based electronic device; the first junction relay is electrically disposed only between the main battery and the charging system electronic device, and the second junction relay is electrically disposed only between the charging system electronic device and the electrically powered system-based electronic device. a main battery; a charging system electronic device including a battery charger and a 12V voltage transformer configured to charge a vehicle-mounted electric power supply that includes the main battery and the battery of low voltage system; an electrically powered system-based electronic device including a booster, an auxiliary machine and a power drive unit that includes an inverter configured to convert direct-current power of the main battery into alternating-current power, thereby driving a motor for travelling; a first high-voltage electric wire that connects the charging system electronic device and the electrically powered system-based electronic device to any one of the positive electrode side and the negative electrode side of the main battery; and a second high-voltage electric wire that connects the charging system electronic device and the electrically powered system-based electronic device to the other one of the positive electrode side and the negative electrode side of the main battery, wherein the booster is connected in series to the first and second high-voltage electric wires (13, 14) and the auxiliary machine and the electrically powered system-based electronic device are branch-connected to the first and second high-voltage electric wires (13, 14), and the electrically powered system-based electronic device and the charging system electronic device are electrically disposed in parallel to the main battery, and the electric vehicle further comprises: a first junction relay capable of isolating the first high-voltage electric wire; and a second junction relay capable of isolating the second high-voltage electric wire, a first junction relay capable of isolating the first high-voltage electric wire; and a second junction relay capable of isolating the second high-voltage electric wire, the first junction relay is electrically disposed between the main battery and the charging system electronic device, and a first pre-charge relay that bypasses the first junction relay is electrically disposed in parallel with the first junction relay, and the second junction relay is electrically disposed between the charging system electronic device and the electrically powered system-based electronic device, characterized in that the charging system electronic device is electrically disposed between the main battery and the electrically powered system-based electronic device; the first junction relay is electrically disposed only between the main battery and the charging system electronic device, and the second junction relay is electrically disposed only between the charging system electronic device and the electrically powered system-based electronic device.