A printing system comprising: a printer, configured to perform printing on a medium; a processing device, configured to perform predetermined processing on the medium on which the printer has performed printing; a printer control unit, configured to control the printer; a processing device control unit, configured to control the processing device; a data creating unit, configured to create printing data for performing printing on the medium by the printer and processing data for performing processing on the medium on which printing is performed by the processing device; and a data processor, configured to receive the printing data and the processing data created by the data creating unit, transmit the received printing data to the printer control unit, and transmit the received processing data to the processing device control unit, characterized in that the data processor creates alignment data for aligning the medium in the processing device based on the printing data and the processing data, and transmits the alignment data to the printer control unit, and the printer control unit controls the printer based on the alignment data received from the data processor to print an alignment mark on the medium wherein the processing device is a cutting device, configured to cut the medium after printing in a predetermined shape, the processing data is cutting data for cutting the medium after printing in a predetermined shape, the printer control unit controls the printer based on the printing data received from the data processor to perform printing on the medium, the printer and the cutting device are arranged in such a way that the medium after printing is to be carried from the printer to the cutting device by a user manually set to the cutting device by using the alignment mark, and the processing device control unit controls the cutting device based on the cutting data received from the data processor to cut the medium. a printer, configured to perform printing on a medium; a processing device, configured to perform predetermined processing on the medium on which the printer has performed printing; a printer control unit, configured to control the printer; a processing device control unit, configured to control the processing device; a data creating unit, configured to create printing data for performing printing on the medium by the printer and processing data for performing processing on the medium on which printing is performed by the processing device; and a data processor, configured to receive the printing data and the processing data created by the data creating unit, transmit the received printing data to the printer control unit, and transmit the received processing data to the processing device control unit, characterized in that the data processor creates alignment data for aligning the medium in the processing device based on the printing data and the processing data, and transmits the alignment data to the printer control unit, and the printer control unit controls the printer based on the alignment data received from the data processor to print an alignment mark on the medium wherein the processing device is a cutting device, configured to cut the medium after printing in a predetermined shape, the processing data is cutting data for cutting the medium after printing in a predetermined shape, the printer control unit controls the printer based on the printing data received from the data processor to perform printing on the medium, the printer and the cutting device are arranged in such a way that the medium after printing is to be carried from the printer to the cutting device by a user manually set to the cutting device by using the alignment mark, and the processing device control unit controls the cutting device based on the cutting data received from the data processor to cut the medium.