The present invention more easily and accurately corrects irregularities in density that can occur in printed images from thermal transfer printers due to mechanical variations or variations in thermal properties in the thermal heads, as compared to cases not having the present configuration. The thermal transfer printer is provided with: a thermal head that has a plurality of heat-generating bodies and that prints images on paper by heating the plurality of heat-generating bodies and transferring ink to the paper; a memory unit for storing a first correspondence relationship between the heat-generating bodies in the thermal head and correction amounts of energy to be applied to the heat-generating bodies prepared from a density distribution of a test image printed on the basis of image data of a single tone, and a second correspondence relationship between the density of an image to be printed and a correction amount adjustment factor; and a control unit for correcting the energy applied to the plurality of heat-generating bodies by an amount obtained by multiplying the correction amount for each heat-generating body obtained by the first correspondence relationship with the adjustment factor obtained by the second correspondence relationship, according to the density of an image to be newly printed.