An image forming apparatus (1 a), comprising: an image reader that reads an original document to generate image data; a storage unit that accumulates and stores print data; a storage control unit that, (a) when print data having a print setting set by an information processor are transmitted to the image forming apparatus, causes the storage unit to store the print setting information about the print setting and the print data transmitted from the information processor, (b) when the image data is generated by the image reader, causes the storage unit to store the generated image data, as the print data not retaining any print setting information; a print accepting unit that accepts a selected input of the print data stored in the storage unit; an image forming unit that prints out an image onto a sheet; a determination unit that, when the print accepting unit accepts a selected input of a plurality of print data, determines whether the plurality of print data include both print data retaining print setting information and print data not retaining any print setting information; a display control unit (301 a) that causes a display unit to display a message about invalidation of the print setting information retained in the print data, when the determination unit determines that the print data accepted by the print accepting unit include both the print data retaining the print setting information and the print data not retaining any print setting information; an agreement accepting unit that accepts a selected input about whether to agree to the message about invalidation of the print setting information; a print setting accepting unit that accepts a setting input of same print setting for the plurality of print data when the agreement accepting unit accepts the selected input about agreement; and a print control unit that when the agreement accepting unit accepts the selected input about agreement, invalidates the print setting information retained in the print data accepted by the print accepting unit, and causes the image forming unit to execute printing based on the plurality of print data by using the print setting accepted by the print setting accepting unit, wherein the display control unit (301 a) causes the display unit not to display the message when the determination unit determines that the print data accepted by the print accepting unit does not include both the print data retaining the print setting information and the print data not retaining any print setting information, the print control unit stops the printing when the agreement accepting unit accepts a selected input about disagreement. an image reader that reads an original document to generate image data; a storage unit that accumulates and stores print data; a storage control unit that, (a) when print data having a print setting set by an information processor are transmitted to the image forming apparatus, causes the storage unit to store the print setting information about the print setting and the print data transmitted from the information processor, (b) when the image data is generated by the image reader, causes the storage unit to store the generated image data, as the print data not retaining any print setting information; a print accepting unit that accepts a selected input of the print data stored in the storage unit; an image forming unit that prints out an image onto a sheet; a determination unit that, when the print accepting unit accepts a selected input of a plurality of print data, determines whether the plurality of print data include both print data retaining print setting information and print data not retaining any print setting information; a display control unit (301 a) that causes a display unit to display a message about invalidation of the print setting information retained in the print data, when the determination unit determines that the print data accepted by the print accepting unit include both the print data retaining the print setting information and the print data not retaining any print setting information; an agreement accepting unit that accepts a selected input about whether to agree to the message about invalidation of the print setting information; a print setting accepting unit that accepts a setting input of same print setting for the plurality of print data when the agreement accepting unit accepts the selected input about agreement; and a print control unit that when the agreement accepting unit accepts the selected input about agreement, invalidates the print setting information retained in the print data accepted by the print accepting unit, and causes the image forming unit to execute printing based on the plurality of print data by using the print setting accepted by the print setting accepting unit, wherein the display control unit (301 a) causes the display unit not to display the message when the determination unit determines that the print data accepted by the print accepting unit does not include both the print data retaining the print setting information and the print data not retaining any print setting information, the print control unit stops the printing when the agreement accepting unit accepts a selected input about disagreement.