A drive device to rotatively drive N number of image carriers. The drive device includes a single drive motor to generate torque to be transmitted to the image carriers, N number of drive gears to transmit the torque to the image carriers, an input gear rotatively driven by the torque and engaging a first drive gear to transmit the torque to the first drive gear, and N−1 number of idler gears provided between each of the drive gears, respectively, to transmit the torque from the drive gears provided on an upstream side to the drive gears provided on a downstream side in a direction of transmission of torque. The torque generated by the drive motor is sequentially transmitted from the first drive gear to the Nth drive gear via the idler gears to rotatively drive the image carriers.