There is provided an image forming apparatus and a control method for the same in which the reading size for an original is controlled according to various executing conditions while troublesome operations for a user are reduced. To accomplish this, at the time of reading an original, the image forming apparatus confirms a pre-registered executing condition and sets the reading size for the original according to the executing condition. Specifically, if an appropriate original size is pre-registered, that original size is set as the reading size for the original. Even if the original size is not pre-registered by the user, an original size entered with minimum user operations required of the user is set as the reading size.