In a line sensor including color filters that are periodically disposed in a light-receiving-element row, a problem called a “mixture of colors” occurs. A “mixture of colors” occurs when light that has been transmitted through a color filter differing from a color filter corresponding to a light receiving element is incident upon the light receiving element.
In a CMOS sensor 107 including a light-receiving-element row in which a plurality of photodiodes 1204 are disposed side by side in a main scanning direction and a plurality of color filters 1202 that are disposed in correspondence with the plurality of photodiodes 1204, the center of each color filter 1202 is displaced in a direction of the center of the light-receiving-element row from the center of the photodiode 1204 corresponding to the color filter.