A solid-state imaging apparatus includes a plurality of pixels arranged two-dimensionally in a matrix, a reference signal generating circuit adapted to generate a ramp signal, a counter circuit adapted to perform a counting operation according to output of the ramp signal, comparators arranged on a column by column basis and adapted to compare signals read out of the pixels with the ramp signal, and memories arranged on a column by column basis and adapted to store digital data, wherein if output of the comparator is not changed during an AD conversion period, digital data of a predetermined value is stored in the memory. The solid-state imaging apparatus implements overflow handling using a simplified circuit configuration.