Control information from a plurality of applications 1000 is written into a shared memory 101 as needed. A communication part 105 transmits the control information written in the shared memory 101 to a DHM 200 in each transmission cycle which is constant. In a management table, a plurality of allowable delay times is defined, the allowable delay time being a delay time allowable at an urgent transmission of the control information. A transmission timing notification part 106 divides a transmission cycle into time slots each of which is equal to or shorter than the shortest allowable delay time defined in the management table. The communication part 105 transmits the control information in the shared memory 101 to the DHM 200 before arrival of the transmission cycle, in a unit of time slot.