Abstract: An electronic control unit includes: a first processing unit that is configured to execute predetermined arithmetic processing and generate a first control signal for controlling the vehicle; a second processing unit that is redundantly disposed with the first processing unit and is configured to generate a second control signal for controlling the vehicle; a first power supply circuit that is configured to generate power for operating the first processing unit based on power supplied from a first power supply device mounted in the vehicle; a second power supply circuit that is configured to generate power for operating the second processing unit based on power supplied from a second power supply device mounted in the vehicle; and a communication line that communicably connects the first processing unit and the second processing unit to each other. The communication line includes a pair of physical layer devices and a capacitor.