To surely prevent malfunction of an apparatus in the event of submergence accident of a vehicle, by detecting sequence of a plurality of contact-point parts being turned on, of an operation switch functioning interlockedly with operation, judging operator's intention based on the sequence, and controlling on/off operation conduction of the apparatus.

Of a plurality of contact-pojnt parts SW(n) of an operation switch 90, contact points on one side are grounded while contact points on the other side are pulled up to a power supply via resistors Rp and connected to an I/O interface 140 of a control part 300, and power supply voltage Vcc is inputted thereinto. An on-signal Sg(n) from this operation/input part 100 is inputted into the control part 300 equipped with a CPU, and operation of the switch 90 is judged by the use of a ROM 120, etc., storing a simultaneously judging program 121, a sequence-judging program 122, an A/D conversion program 123, etc. From the sequence and time-interval of on-motions, it is judged whether human operation by an operator is being made, or leakage due to submergence, etc., is happening, and a motor 160 for power windows, a solenoid 80 for door lock, and the like are controlled accordingly.