An image forming apparatus includes a light source that outputs a plurality of laser beams and a control unit that adjusts the light intensity of each of the laser beams. The control unit calculates a correction value so that, when the laser beam is driven by a control value calculated by correcting a common control value using the correction value and adding a threshold to the corrected control value, the light intensity of the laser beam is equal to a target light intensity. The threshold is calculated so that, when the laser beam is driven by a control value calculated by multiplying the corrected control value by a predetermined factor, and adding the threshold to the multiplied control value, the light intensity of the laser beam is equal to the target light intensity multiplied by the predetermined factor.