Optical member and image reading device

An optical member, comprising:

• a lens array including lens bodies that are arranged in a line in a main scanning direction and are configured to converge light from an object-to-be-read;
• and
• transmissive optical elements made of a material having a uniform refractive index, the transmissive optical elements being disposed at positions nearer the object-to-be-read than the corresponding lens bodies being disposed or at positions farther from the object-to-be-read than the corresponding lens bodies being disposed, the transmissive optical elements having a columnar shape extending along optical axes of the lens bodies, the transmissive optical elements being configured to allow light incident through one end faces to exit through other end faces, wherein
• the lens bodies each have, in a cross section in an optical-axis orthogonal plane, a length in the main scanning direction at a first position shorter than a length in the main scanning direction at a second position through the optical axis, the optical-axis orthogonal plane being orthogonal to the optical axis of the lens body, the first position being deviated from the second position in a sub-scanning direction intersecting the main scanning direction,
• the transmissive optical elements each have, in a cross section in the optical-axis orthogonal plane, a length in the main scanning direction at a third position shorter than a length in the main scanning direction at a fourth position through a central axis of the transmissive optical element, the third position being deviated from the fourth position in the sub-scanning direction, and
• the optical axes of the lens bodies are deviated, at least in the sub-scanning direction, from the central axes of the transmissive optical element corresponding to the respective lens bodies by amounts greater than manufacturing errors in the transmissive optical elements or errors in arrangement of the transmissive optical elements such that an end face of the lens body to which an end face of each of the transmissive optical elements is opposed is not end faces of two or more of the lens bodies but an end face of a corresponding one of the lens bodies.