A printing apparatus for performing printing under control of a head controller which receives image data, and which is connected to a print head for printing. The head controller includes an image data shaping unit for shaping the image data into print data corresponding to the print head, a sequence information generating unit for generating sequence information, based on the print data, showing operation at a time of printing by the print head, a data guarantee information adding unit for adding data guarantee information to the print data and the sequence information, for error detection based on the print data and the sequence information, a readout unit for reading print information including the print data, the sequence information, and the data guarantee information, and an information inspecting unit for inspecting propriety of the print information based on the data guarantee information and the sequence information read by the readout unit.