Image forming apparatus

An endless belt is extended over extending rollers, and carries a toner image transferred from an image carrier or a transfer sheet. The endless belt includes a front-side reinforcing member and a rear-side reinforcing member, and a guide member for preventing meandering fixed over an approximately entire circumference on the rear-side reinforcing member. The extending rollers include a step portion provided in an end area in an axial direction facing to the rear-side reinforcing member, which has a diameter smaller than a center area in the axial direction. The front-side reinforcing member has a width wider than a width of the rear-side reinforcing member.