An image writing device includes an exposure unit including an exposure head, writing an image onto an image bearing surface of a photoconductor by causing the exposure head to repeatedly expose; and a write control unit transmitting image data to be written by the exposure unit to the exposure unit on a one-line basis. Further the write control unit generates a write cycle reference signal having a cycle corresponding to writing resolution, counts a clock by a predetermined count value, generates a write cycle signal by delaying the write cycle reference signal by a time period, generates a data request signal to request transmission of one line of the image data to a controller unit based on the write cycle signal, and stores the one line of the image data transmitted from the controller unit.