A printing data generation device generating printing data, to be supplied to a printer that performs printing on a printing sheet, based on submission data, the printing data generation device comprising: a layout acquisition portion configured to acquire a layout including a page position region of each of pages in a second direction perpendicular to a first direction, which is a printing sheet feeding direction, the page position region being on a unit printing sheet, which is a one-unit printing region; a page position determination portion configured to determine an actual position of each of the pages on the unit printing sheet when the printing is performed by the printer, the actual position being determined based on the page position region of each of the pages and the submission data; an overall imposition information generation portion configured to generate overall imposition information that specifies an imposition layout of all pages to be printed by the printer, the overall imposition information being generated based on the actual position of each of the pages determined by the page position determination portion and the submission data; and a rasterization processing portion configured to execute a rasterization process on the submission data based on the overall imposition information to generate the printing data; wherein the page position determination portion changes a size of the page position region in accordance with a second direction length of each of the pages included in the submission data while fixing one end or the other end, in the second direction, of the page position region as a fixed end, and determines the actual position of each of the pages on the unit printing sheet, and wherein regarding each of the pages on the unit printing sheet, the same end of the one end or the other end, in the second direction, of the page position region is regarded as the fixed end. a layout acquisition portion configured to acquire a layout including a page position region of each of pages in a second direction perpendicular to a first direction, which is a printing sheet feeding direction, the page position region being on a unit printing sheet, which is a one-unit printing region; a page position determination portion configured to determine an actual position of each of the pages on the unit printing sheet when the printing is performed by the printer, the actual position being determined based on the page position region of each of the pages and the submission data; an overall imposition information generation portion configured to generate overall imposition information that specifies an imposition layout of all pages to be printed by the printer, the overall imposition information being generated based on the actual position of each of the pages determined by the page position determination portion and the submission data; and a rasterization processing portion configured to execute a rasterization process on the submission data based on the overall imposition information to generate the printing data; wherein the page position determination portion changes a size of the page position region in accordance with a second direction length of each of the pages included in the submission data while fixing one end or the other end, in the second direction, of the page position region as a fixed end, and determines the actual position of each of the pages on the unit printing sheet, and