PURPOSE: To instantaneously rearrange a signal into the same data array with a parallel signal before parallel/serial conversion as to the serial/parallel converting circuit with the indeterminacy removing function.

CONSTITUTION: This circuit is equipped with a serial/parallel conversion part 1 which converts a parallel/serial-converted serial signal into a parallel signal, a parallel/serial conversion part 2 which converts the parallel signal converted by the serial/parallel conversion part 1 into a serial signal, a comparison and decision part 3 which compares the serial signal from the parallel/serial conversion part 2 with the serial signal inputted to the serial/parallel conversion part 1 and decides whether or not the conversion by the serial/parallel conversion part 1 is performed at specific timing, and a correction part 4 which corrects the parallel signal from the serial/parallel conversion part 1 on the basis of the comparison and decision result of the comparison and decision part 3 unless the conversion by the serial/parallel conversion part 1 is done at the specific timing.