A sheet processing apparatus that forms a portion-to-be-processed on a sheet having pre-products, wherein the sheet is one of a plurality of sheets that are sent out one by one, the sheet processing apparatus comprising: at least one processing tool (20a, 20b, 21a, 21b, 22a, 22b, 23a, 23b) that takes a processable state in which the portion-to-be-processed is allowed to be formed and an unprocessable state in which the portion-to-be-processed is not allowed to be formed; and a control unit that controls an operation state of the at least one processing tool (20a, 20b, 21a, 21b, 22a, 22b, 23a, 23b), wherein a margin is provided around each of the pre-products on the sheet, characterized in that the control unit is configured to control the at least one processing tool (20a, 20b, 21a, 21b, 22a, 22b, 23a, 23b) such that when the at least one processing tool (20a, 20b, 21a, 21b, 22a, 22b, 23a, 23b) moves from formation of a certain portion-to-be-processed in a certain pre-product on the sheet to formation of a next portion-to-be-processed of the same type as the certain portion-to-be-processed in a next pre-product on the sheet, a processable state holding process is executed to form a continuous portion-to-be-processed in which the certain portion-to-be-processed in the certain pre-product, a marginal portion-to-be-processed in the margin, and the next portion-to-be-processed in the next pre-product are formed continuously, by holding the processable state and forming the marginal portion-to-be-processed in the margin, and wherein when the at least one processing tool (20a, 20b, 21a, 21b, 22a, 22b, 23a, 23b) moves relatively with respect to the sheet so as to draw an inversed C-shaped or C-shaped trajectory in the conveyance perpendicular direction, the conveyance direction, and the conveyance perpendicular direction, the at least one processing tool (20a, 20b, 21a, 21b, 22a, 22b, 23a, 23b) is located outside the sheet. at least one processing tool (20a, 20b, 21a, 21b, 22a, 22b, 23a, 23b) that takes a processable state in which the portion-to-be-processed is allowed to be formed and an unprocessable state in which the portion-to-be-processed is not allowed to be formed; and a control unit that controls an operation state of the at least one processing tool (20a, 20b, 21a, 21b, 22a, 22b, 23a, 23b), wherein a margin is provided around each of the pre-products on the sheet, characterized in that the control unit is configured to control the at least one processing tool (20a, 20b, 21a, 21b, 22a, 22b, 23a, 23b) such that when the at least one processing tool (20a, 20b, 21a, 21b, 22a, 22b, 23a, 23b) moves from formation of a certain portion-to-be-processed in a certain pre-product on the sheet to formation of a next portion-to-be-processed of the same type as the certain portion-to-be-processed in a next pre-product on the sheet, a processable state holding process is executed to form a continuous portion-to-be-processed in which the certain portion-to-be-processed in the certain pre-product, a marginal portion-to-be-processed in the margin, and the next portion-to-be-processed in the next pre-product are formed continuously, by holding the processable state and forming the marginal portion-to-be-processed in the margin, and wherein when the at least one processing tool (20a, 20b, 21a, 21b, 22a, 22b, 23a, 23b) moves relatively with respect to the sheet so as to draw an inversed C-shaped or C-shaped trajectory in the conveyance perpendicular direction, the conveyance direction, and the conveyance perpendicular direction, the at least one processing tool (20a, 20b, 21a, 21b, 22a, 22b, 23a, 23b) is located outside the sheet.