It is an object of this invention to provide an image forming apparatus capable of coping suitably with the fluctuation in a used consumption amount at the predetermined period as well as grasping in advance feasibility of a use. To achieve the above, an image forming apparatus according this invention has an entry section for entering image forming data; a using amount storage means for storing a using amount of a consumption used at a predetermined period for purpose of image formation; a setting means for setting a usable consumption amount of the predetermined period; and a usable amount determining means for determining the usable consumption amount of each determined period, the usable amount determining means for determining after the predetermined period the usable amount of a subsequent period corresponding to the using amount.