The invention makes it possible to perform effective A/D conversion on pixel signals read from a pixel array part, to achieve a reduction in power consumption and reductions in the size and the price of an image pickup device as well as simplification of the construction of the device, and to realize a high-quality image output. The device includes an pixel array part having a plurality of unit pixels, a CDS (correlated double sampling) circuit, and an A/D converter. A pixel signal read from a pixel array part via a signal line is subjected to CDS processing (noise elimination processing) in the CDS circuit, and then this pixel signal is inputted into the A/D converter which performs A/D conversion on the pixel signal. The A/D converter includes a ΔΣ modulator and a digital filter to perform highly accurate A/D conversion. The invention can also be applied to a construction in which an A/D converter is provided at the front stage of the CDS circuit.