When a fixed-cycle transmission timing arrives, a fixed-period communication processing section transmits data in a shared memory to a BCM. An event table storage section stores an event table that indicates a condition of data to be transmitted by an event communication processing section and a permitted delay time, which is the period of time permitted starting from when the data satisfying the condition is extracted, until the data is transmitted. An event detecting section extracts the data in the shared memory satisfying the condition indicated by the event table. The event communication processing section transmits to the BCM the data extracted by the event detecting section, before the arrival of the transmission timing of the fixed-period communication processing section, and by the timing at which the permitted delay time elapses from the time of the data extraction by the event detecting section.