A solid-state image pickup apparatus has: a pixel area having unit pixels arranged in a two-dimensional matrix; a plurality of analog/digital converters, each provided for the unit pixels on the same column; a plurality of first/second memory units, provided to respective analog/digital converters, for storing the digital signals of one/another row; and a digital signal processing unit for generating an output signal based on the signals from the first and second memory units, wherein the first and second memory units store the digital signals of a same row at a non-addition operation and store the digital signals of different rows at an addition operation, and wherein, at the non-addition operation, if one of the first and second memory units on a same column is defective, the digital signal processing unit generates the output signal based on the signal from the other one of the units on the same column.