Image reading device and image forming apparatus

An image reading device comprising:

• a top plate in which a placement surface on which an original document is placed is formed;
• an optical imaging system that is arranged above the placement surface and images the original document;
• a support frame of which a base end portion is attached to an apparatus main body and that supports the optical imaging system in a part on a tip end side, wherein the support frame includes a pair of vertical frames that are both side parts of the apparatus main body in an apparatus width direction standing upward from a far side part of the apparatus main body in an apparatus depth direction, and a horizontal frame that extends across upper end portions of the pair of vertical frames;
• an adjustment bracket for adjusting a position of the optical imaging system with respect to the placement surface in the apparatus width direction and the apparatus depth direction;
• and
• a cover that covers and encompasses the adjustment bracket and the support frame.