A drive transmission mechanism includes a drive transmission gear, an output-side coupling, and a first drive transmission member. The drive transmission gear includes a cylindrical boss formed at the rotation center, a circular rim concentric with the boss, and a web coupling the boss with the rim. The output-side coupling outputs a driving force of the drive transmission gear to a driven member. The first drive transmission member has higher rigidity than the drive transmission gear, and transmits the driving force of the drive transmission gear to the output-side coupling by rotating together with the drive transmission gear. The output-side coupling incline in an arbitrary direction relative to the rotation axis of the first drive transmission member, and the driving force from the drive transmission gear is transmitted to the outer circumferential rim of the first drive transmission member.