To provide an image forming apparatus having a scanning function and an image forming method by which images of right and left pages of a book are not printed upside down when the book is scanned using the image forming apparatus having a scanning function, and an image forming apparatus.

The image forming method comprises the image forming apparatus having the scanning function and a host computer connected to the image forming apparatus and includes: a storage step of allowing the host computer to receive scanned image data from the image forming apparatus and store the scanned image data; a determination step of allowing a control unit of the host computer to determine whether a scanned image belongs to a left page or a right page of a book; and a rotation step of rotating, if the scanned image belongs to a right page, the scanned image 180 degrees and storing the rotated image.