A voltage detector includes a comparison unit which is equipped with a plurality of comparators and which is configured to compare a threshold voltage and determination voltages corresponding to each comparator and output a first result of High or Low for each comparator and configured to compare an input voltage and the determination voltages and output a second result of High or Low for each comparator, and a determination unit configured to determine based on the first result and the second result whether or not the input voltage is less than or equal to the threshold voltage.