To shorten transmission delay of data by effectively using a bus to improve time efficiency of data transmission.

A specified piece of data is transmitted to the bus by a node which obtains a transmission right by circulating the transmission right between respective nodes 1a to 1c connected to the bus 3 in a predetermined order with respect to a vehicle multiple communication equipment, the data block is generated by dividing the data into plural blocks by a block dividing part 12, each of the generated blocks is judged whether it is changed by an occurrence of an event or not by every generated data block by a changing block judging part 13 and when the data block is judged to be changed, the changed data block is extracted from the block dividing part and transmitted to the bus by a data transmitting part 15.