An image forming apparatus capable of forming wide images, includes: an exposing unit having a plurality of LED (light-emitting diode) heads arranged alternately in a main scanning direction, in which the resolution of an LED row formed in at least one of the plurality of LED heads is higher than the resolution of image data in a main scanning direction; and a lighting control unit that controls to turn on or turn off dots in the LED row such that the exposing position of a photoconductive drum is moved in the unit of dots of the high resolution LED row.