A printing device comprising: a printing-medium running unit that causes a printing medium to run; a sheet supply unit that supplies a thermal transfer sheet onto the printing medium, the thermal transfer sheet having at least an image protection layer to be thermally transferred to the printing medium; a thermal head having a plurality of heating elements that are linearly located in a direction perpendicular to a direction along which the printing medium runs; and a control means that drives and controls the thermal head; wherein: the control means is configured to drive and control the thermal head to thermally transfer the image protection layer of the thermal transfer sheet to the printing medium, and to form a roughened pattern on the image protection layer; the printing device being characterized in that the control means is configured to form the roughened pattern composed of a plurality of pixels which are arranged like a grid and include high-energy pixels and low-energy pixels between the high-energy pixels, and the roughened pattern is made based on a corrected pattern that is obtained by correcting a basic pattern that is a pattern including an island portion formed of a mass of the plurality of high-energy pixels, the island portion including high-energy pixels forming an edge area and high-energy pixels forming an inner area surrounded by the high-energy pixels of the edge area, such that the high-energy pixels forming the inner area surrounded by the high-energy pixels forming the edge area of the island portion of the basic pattern are converted to the low-energy pixels. a printing-medium running unit that causes a printing medium to run; a sheet supply unit that supplies a thermal transfer sheet onto the printing medium, the thermal transfer sheet having at least an image protection layer to be thermally transferred to the printing medium; a thermal head having a plurality of heating elements that are linearly located in a direction perpendicular to a direction along which the printing medium runs; and a control means that drives and controls the thermal head; wherein: the control means is configured to drive and control the thermal head to thermally transfer the image protection layer of the thermal transfer sheet to the printing medium, and to form a roughened pattern on the image protection layer; the printing device being characterized in that the control means is configured to form the roughened pattern composed of a plurality of pixels which are arranged like a grid and include high-energy pixels and low-energy pixels between the high-energy pixels, and the roughened pattern is made based on a corrected pattern that is obtained by correcting a basic pattern that is a pattern including an island portion formed of a mass of the plurality of high-energy pixels, the island portion including high-energy pixels forming an edge area and high-energy pixels forming an inner area surrounded by the high-energy pixels of the edge area, such that the high-energy pixels forming the inner area surrounded by the high-energy pixels forming the edge area of the island portion of the basic pattern are converted to the low-energy pixels. the control means is configured to drive and control the thermal head to thermally transfer the image protection layer of the thermal transfer sheet to the printing medium, and to form a roughened pattern on the image protection layer; the printing device being characterized in that the control means is configured to form the roughened pattern composed of a plurality of pixels which are arranged like a grid and include high-energy pixels and low-energy pixels between the high-energy pixels, and the roughened pattern is made based on a corrected pattern that is obtained by correcting a basic pattern that is a pattern including an island portion formed of a mass of the plurality of high-energy pixels, the island portion including high-energy pixels forming an edge area and high-energy pixels forming an inner area surrounded by the high-energy pixels of the edge area, such that the high-energy pixels forming the inner area surrounded by the high-energy pixels forming the edge area of the island portion of the basic pattern are converted to the low-energy pixels.