An image forming apparatus including a power transmission unit having a driving source, at least one image receptor which is rotatably driven by the driving source and on which a latent image is formed by exposure, and a power transmission unit which transmits power from the driving source to the image receptor. The power transmission unit includes an image receptor axial gear formed on the same axis as the image receptor, and a plurality of intermediate gears which transmits the power from the driving source to the image receptor axial gear. The number Tn of teeth of an n-th one of the plurality of intermediate gears with respect to the image receptor axial gear satisfies the following Inequality: (I/Rn)−0.2≦Tn≦(I/n)+0.2, where, Rn is a reduction ratio from the n-th intermediate gear to the image receptor axial gear and I and n are a natural number.