1. A nail print apparatus which prints on a nail comprising: an imaging section which obtains a finger image by imaging a finger including a nail to be printed; a finger dimension obtaining section which obtains a dimension of the finger from the finger image obtained by the imaging section; a storage section which stores a plurality of nail region extracting models including outlines with shapes different from each other; a model selecting section which selects one specific nail region extracting model from the plurality of nail region extracting models stored in the storage section based on the dimension of the finger obtained by the finger dimension obtaining section; a region specifying section which specifies a nail region which is to be a print target of the finger by fitting the specific nail region extracting model selected by the model selecting section to a region of the nail in the finger image; and a printing section which includes a printing head to apply ink to the nail region specified by the region specifying section; wherein the storage section further stores a threshold value of the dimension of the finger corresponding to the nail region extracting models; and wherein the model selecting section selects the specific nail region extracting model based on a comparison between the dimension of the finger obtained by the finger dimension obtaining section and the threshold value stored in the storage section.