There is disclosed an image forming apparatus comprising input means for inputting print data from the exterior, ID setting means for setting an ID for each page of the print data inputted by the input means, print condition designation means for designating the print condition, corresponding to the ID set by the ID setting means, print reservation means for reserving a print operation by storing the ID and the print condition in a print reservation memory, control means for causing the reserved print operation to be executed according to the content of the print reservation memory, and reservation cancellation means adapted, upon receiving an instruction to cancel a print reservation, to erase the corresponding ID and print condition from the print reservation memory, if a sheet corresponding to the designated ID in the print reservation memory is in a stand-by state for sheet feeding.