An image forming apparatus includes an image forming portion for forming an image on a sheet by using a developer including toner, a feeding belt for feeding the sheet, an infrared irradiating portion for irradiating, with infrared radiation, the image on the sheet fed by the feeding belt, and an ultraviolet irradiating portion for irradiating, with ultraviolet radiation, the image on the sheet having been irradiated with the infrared radiation to fix the developer on the sheet by ultraviolet radiation. In addition, a controller controls operations of the feeding belt and the infrared irradiating portion, and causes the infrared irradiating portion to irradiate the feeding belt with the infrared radiation while causing the feeding belt to rotate in a stand-by state in which the controller waits for an execution instruction of an image forming operation in a state in which the image forming operation is capable of being started.