An image forming system is provided with an Image Forming Operation Unit, an Air Cleaning Operation Unit, a power source, and a Control Unit. The Control Unit has a coordinated OFF control function of coordinating a first power supply OFF control for turning off power supply from the power source to the Image Forming Operation Unit and a second power supply OFF control for turning off power supply from the power source to the Air Cleaning Operation Unit, and the coordinated OFF control function is configured to execute the second power supply OFF control when a preset time period elapses after executing the first power supply OFF control. Also, in the image forming system, an air cleaning operation of an air cleaning apparatus is stopped when an image forming apparatus is set to an a night mode or when a fixed time period elapses after the night mode is set. The air cleaning operation of the air cleaning apparatus is restarted when the image forming apparatus is resumed from the night mode.