An image pickup apparatus includes a pixel portion in which pixels are arranged, the pixels each including a first semiconductor region of first conductivity type having signal charges as majority carriers and a second semiconductor region of second conductivity type having signal charges as minority carriers, the second semiconductor region being contiguous to the first semiconductor region, the first semiconductor region being disposed between a surface of a semiconductor substrate. The pixel portion includes a class I pixel and a class II pixel located near a reference contact. A distance between the surface of the semiconductor substrate and the second semiconductor region of the class I pixel is smaller than a distance between the surface of the semiconductor substrate and the second semiconductor region of the class II pixel.