ON-VEHICLE CONTROL DEVICE

A failure detection frequency of failure diagnosis for a cut-off function can be improved. An on-vehicle control device includes a microcomputer that performs a control operation of an external device, a monitoring element that monitors the microcomputer, an output drive circuit that sends a control signal to the external device based on an instruction from the microcomputer, a communication circuit that switches a communication state with another on-vehicle control device based on an instruction from the monitoring element, and an energization cut-off element that energizes and cuts off a power supply voltage to be supplied to the output drive circuit based on an instruction from the monitoring element. The monitoring element independently instructs the switching of the communication state by the communication circuit and the energization and cut-off of the power supply voltage by the energization cut-off element.