Image reading apparatus and image forming apparatus

An image reading apparatus that comprises an original platen and a scanning unit for reading an image on an original put on the original platen, comprising:

• a pull member that pulls the scanning unit;
• a driving pulley that transmits driving force to the pull member;
• a following pulley that the pull member is wound thereon while keeping a state where tension is applied to the pull member;
• and
• a pulley holder having a pulley axis that holds the following pulley rotatably and a lock pawl that can lock the following pulley from a side of the pulley axis and cancel engagement with the following pulley by being tilted toward a side of an axial center of the pulley axis by elastic deformation, wherein
• the lock pawl is arranged on a side of a tension acting direction from the pull member to the following pulley among positions in a circumferential direction of the pulley axis,
• the pulley axis comprises a groove-like notched portion that is formed by notching a part in a circumferential direction thereof, and
• the lock pawl is provided in a position corresponding to the notched portion.