A solenoid valve control device comprising a plurality of solenoid valve modules (161 to 16n), and a communication module, the solenoid valve modules being connected in series to the communication module, the solenoid valve control device further comprising: a transmission line; a receiving line; and a switching line, wherein the transmission line, the receiving line, and the switching line cross the communication module and the plurality of solenoid valve modules, the solenoid valve modules each include a first communication circuit and a second communication circuit, an input terminal of the second communication circuit is connected to the transmission line, and an output terminal of the second communication circuit is connected to the receiving line, wherein a solenoid valve control signal transmitted from the communication module to the transmission line is received by the first communication circuit of each of the solenoid valve modules, and a signal related to diagnostic information is transmitted from the first communication circuit to the transmission line together with the solenoid valve control signal, and wherein the second communication circuit of each of the solenoid valve modules other than the solenoid valve module disposed at a terminal end of the plurality of solenoid valve modules receives a signal from the switching line located in the solenoid valve module disposed next thereto, and the second communication circuit of the solenoid valve module that is disposed at the terminal end and that receives no signal from the switching line transmits the solenoid valve control signal and signals related to the diagnostic information of the plurality of solenoid valve modules to the communication module via the receiving line. the solenoid valve control device further comprising: a transmission line; a receiving line; and a switching line, wherein the transmission line, the receiving line, and the switching line cross the communication module and the plurality of solenoid valve modules, the solenoid valve modules each include a first communication circuit and a second communication circuit, an input terminal of the second communication circuit is connected to the transmission line, and an output terminal of the second communication circuit is connected to the receiving line, wherein a solenoid valve control signal transmitted from the communication module to the transmission line is received by the first communication circuit of each of the solenoid valve modules, and a signal related to diagnostic information is transmitted from the first communication circuit to the transmission line together with the solenoid valve control signal, and wherein the second communication circuit of each of the solenoid valve modules other than the solenoid valve module disposed at a terminal end of the plurality of solenoid valve modules receives a signal from the switching line located in the solenoid valve module disposed next thereto, and the second communication circuit of the solenoid valve module that is disposed at the terminal end and that receives no signal from the switching line transmits the solenoid valve control signal and signals related to the diagnostic information of the plurality of solenoid valve modules to the communication module via the receiving line.