A nail printing device recognizes, as a first nail contour, a nail contour from a first nail image obtained by photographing a nail of a specific finger/toe, displays the first nail contour on the basis of data of the first nail contour stored in a storage section, and performs an adjustment of the first nail contour on the basis of an adjustment portion specified to the first nail contour and obtains an adjusted nail contour. After that the device recognizes, as a second nail contour, a nail contour from a second nail image obtained by photographing the nail of the specific finger/toe, reflects the adjustment performed to the first nail contour, in the second nail contour, obtains an adjusted recognized nail contour, and controls a print head to perform printing in a region of the adjusted recognized nail contour.