An image forming apparatus may include a sensor which detects a density of a patch image formed on an image carrier; an image quality control section which controls an image forming condition based on a detection value of the sensor; and a judging section which judges if the detection value has a tendency of increasing or decreasing, or not, wherein, the image quality control section compensates the image forming condition with a first compensating amount in case when the detection value does not have the tendency of increasing nor decreasing, and compensates the image forming condition with a second compensating amount of which absolute value is larger than an absolute value of the first compensating amount corresponding to the second compensating amount, in case when the detection value has the tendency of increasing or decreasing.