Among the 2481 photoelectric converting devices 33, one of the photoelectric converting devices 33 at one end in the chip CH1, which is at a most upstream position in the main-scanning direction MD, on a side to adjoin none of the chip CH2 or other chips CH3-CH12 may be called as a foremost photoelectric converting device 33. Another one of the photoelectric converting devices 33 at one end in the chip CH12, which is at a most downstream position in the main-scanning direction MD, on a side to adjoin none of the chip CH11 or other chips CH1-CH10 may be called as a rearmost photoelectric converting device 33. In this regard, among the 2481 pixels obtained through the 2481 photoelectric converting devices 33, a pixel obtained through the foremost photoelectric converting device 33 may be called as a foremost pixel, and another pixel obtained through the rearmost photoelectric converting device 33 may be called as a rearmost pixel. In this regard, the terms “foremost” and “rearmost” may not necessarily be related to the frontward direction and the rearward direction concerning the orientation of the image reading apparatus 1 indicated by arrows in FIG. 1. Meanwhile, another one of the photoelectric converting devices 33 in the chip CH7 at a center in the main-scanning direction MD, i.e., the 1241th pixel from the foremost photoelectric converting device 33 and from the rearmost photoelectric converting device 33, may be called as a central photoelectric converting device 33, and a pixel obtained through the central photoelectric converting device 33, which is at a position to face a central position in the main-scanning direction MD on the supporting surface of the sheet tray 2, may be called as a central pixel. In this regard, the 2481 photoelectric converting devices 33 may read a line of image extending along the main-scanning direction MD and obtain a group of 2481 pixels aligning in line along the main-scanning direction MD between the foremost pixel and the rearmost pixel inclusive at a time. Further, the 2481 photoelectric converting devices 33 may obtain a plurality of lines, each containing a group of 2481 pixels, arranged along the conveying direction FD line by line consecutively. In the following description, a main-scanning position MDP, which is a position of the pixels aligning in the main-scanning direction MD, may be expressed by a number, which corresponds to a number of the photoelectric converting device 33 that may read one of the 2481 images as the original sheet GS is conveyed in the conveying direction FD. For example, a main-scanning position MDP being a pixel position for the foremost pixels is expressed by 1; a main-scanning position MDP being a pixel position for the central pixels is expressed by 1241, and a main-scanning position MDP being a pixel position for the rearmost pixels is expressed by 2481.