are off thus a simpler circuit structure is achieved in the variation compared to that of the monitor circuits in the embodiment described earlier and as a result the number of input terminals at the microcomputer 11 can be reduced it is to be noted that while an explanation is given above in reference to the embodiment on an example in which the headlamps constitute the electrical loads in the vehicle the present invention may be adopted in conjunction with vehicle electrical loads other than headlamps for instance the electrical loads may be the left and right turn signal lamps instead namely the present invention may be adopted in conjunction with any electrical loads that are alternately engaged in operation in addition while an explanation is given above in reference to the embodiment on an example in which low beams and high beams at the headlamps constitute vehicle electrical loads the number of electrical loads is not limited to the example of the embodiment furthermore the present invention may be adopted in conjunction with electrical loads in non automotive applications the terms u201c electrical loads u201d as referred to in this context may be regarded to mean electrical or electronic components electrical or electronic elements or electrical or electronic devices while an explanation is given above in reference.