An image forming apparatus is provided with an image forming station including photoconductive drums and adapted to form toner images on surfaces of the respective photoconductive drums, and a drive control unit for rotating and driving the photoconductive drums. The image forming station includes a reference pulse output section for generating a reference pulse having a cycle equal to or an integral multiple of a rotation cycle of the photoconductive drums and outputting the reference pulse to the drive control unit. The drive control unit includes a phase peak detector for detecting phase peaks of surface speeds of the photoconductive drums, a phase difference detector for detecting phase differences between an edge of the reference pulse and the phase peaks, and a phase synchronization controller for synchronizing phases of the surface speeds of the photoconductive drums by controlling rotation speeds of the photoconductive drums according to the phase differences.