A determination system comprising: an imaging data acquisition device that is configured to capture an image of a printed surface (B) of a printed product (A) to acquire imaging data of the captured image; and a determination device that is configured to determine, based on the imaging data acquired by the imaging data acquisition device , a printing method used to produce the printed surface (B) of the printed product (A) for which the image is captured by the imaging data acquisition device , wherein the determination device is further configured to select (S1) a plurality of determination areas included in the captured image from the imaging data acquired by the imaging data acquisition device , acquire determination data based on a line-segment image included in each of the selected plurality of determination areas, compare the acquired determination data between two determination areas, and acquire, based on a result of the comparison, a determination value for determining a printing method used to produce the printed surface (B) of the printed product (A), and determine, based on the acquired determination value, a printing method used to produce the printed surface (B) of the printed product (A), wherein the determination device is further configured to determine that the printed surface (B) is a printed surface printed with a printer that performs printing through scanning using a driving system in a case where the determination value indicates that an undulation degree indicating a degree of undulations of a line-segment image is greater than or equal to a preset determination threshold, or determine that the printed surface (B) is a printed surface printed with a plate in a case where the determination value indicates that the undulation degree is less than the determination threshold. an imaging data acquisition device that is configured to capture an image of a printed surface (B) of a printed product (A) to acquire imaging data of the captured image; and a determination device that is configured to determine, based on the imaging data acquired by the imaging data acquisition device , a printing method used to produce the printed surface (B) of the printed product (A) for which the image is captured by the imaging data acquisition device , wherein the determination device is further configured to select (S1) a plurality of determination areas included in the captured image from the imaging data acquired by the imaging data acquisition device , acquire determination data based on a line-segment image included in each of the selected plurality of determination areas, compare the acquired determination data between two determination areas, and acquire, based on a result of the comparison, a determination value for determining a printing method used to produce the printed surface (B) of the printed product (A), and determine, based on the acquired determination value, a printing method used to produce the printed surface (B) of the printed product (A), wherein the determination device is further configured to determine that the printed surface (B) is a printed surface printed with a printer that performs printing through scanning using a driving system in a case where the determination value indicates that an undulation degree indicating a degree of undulations of a line-segment image is greater than or equal to a preset determination threshold, or determine that the printed surface (B) is a printed surface printed with a plate in a case where the determination value indicates that the undulation degree is less than the determination threshold. <EOS>