An electronic control apparatus 100A is configured in such a way that a CPU 110A reads the conduction current of an opening/closing device 140n in an IPM 190A, by way of serial-parallel converters 114a and 114b and a second multi-channel A/D converter 116b; the opening/closing device 140n is opening/closing-controlled through a serial control signal SRn or a parallel control signal PWMn; and a reading timing control circuit 170n adjusts the reading timing in such a way that, regardless of the kind of the control signal, reading is performed during the period in which the opening/closing device 140n is driven to be closed. As a result, the serial-parallel converter can reduce the number of wiring leads between the IPM and the microprocessor, and the digital conversion value is accurately read, by adjusting the error between the serial-signal timing and the parallel-signal timing.