An image forming apparatus that can reduce the time required for adjustment operations when a first adjustment operation that requires speed change and a second adjustment operation that does not require speed change overlap. When a first adjustment operation that can be performed at a first speed is to be performed during operation at a second speed lower than the first speed, the image formation speed is changed from the second speed to the first speed. When a second adjustment operation that can be performed at a plurality of image formation speeds is to be performed during operation at the second speed, the second adjustment operation is performed while maintaining the second speed. When both the first adjustment operation and the second adjustment operation are to be performed during operation at the second speed, the image formation speed is changed from the second speed to the first speed.