An image forming apparatus include an apparatus body, a cassette, and a size detector to detect a size of a sheet stored in the cassette. An image forming unit forms an image on a sheet fed from the cassette depending on a size setting and a type setting stored in a memory. In addition, a controller executes a first rewrite process to rewrite the size setting in a memory with size information acquired as a detection result of the size detector, if the cassette in an open state is closed, a determination process to determine whether the size information used for rewriting the size setting in the first rewrite process and the type setting stored in the memory satisfy a predetermined combination condition, and a second rewrite process to rewrite the type setting in the memory with predetermined type information that satisfies the combination condition with respect to the size information used for rewriting the size setting in the first rewrite process if the combination condition is not satisfied in the determination process.