An electronic control unit is incorporated as one of a plurality of electronic controllers composing a system for controlling in-vehicle devices on a distributed and mutually-synchronized control manner in a vehicle. The plurality of electronic control units are communicably connected with each other via an in-vehicle network to communicate information including the time-dependent data among the electronic control units. Each electronic control unit comprises a control member, an elapsed-time calculation component, and a validity determination component. The control member performs the control on the basis of time-dependent data acquired in time series relating to the vehicle. The elapsed-time calculation component is configured to calculate an elapsed time elapsing from acquisition of the time-dependent data. The validity determination component is configured to use the calculated elapsed time to determine whether or not the time-dependent data is valid or not for the control in terms of freshness of the time-dependent data.