A vehicle control system for controlling a device mounted on a vehicle includes a plurality of processor cores, and a computation process unit that is required for the control of the device is executed on the plurality of cores. A core failure determination unit compares a result of a computation process executed by the computation process unit at a particular timing on a particular one of the plurality of cores, with a result of a computation process executed at a timing different from the particular timing on another core different from the particular core, to determine that a failure has occurred on the specific core.