A data reception unit carries out reception of data, which consists of a combination of switching noise resistant states and switching noise nonresistant states, over a fixed serial communication time a plurality of times for each fixed serial communication period same as the one or a plurality of the switching periods. A serial communication time setting unit sets the serial communication time different from one or a plurality of the switching periods, based on the switching period, the serial communication period, and the communication speed of the data communication device, so that the starts of all of the switching periods within the serial communication time are consistent with the time of reception of the switching noise resistant state at the time of at least one of the reception of the data among a plurality of times of the reception of the data.