Provided is a labeling device for an automatic test-tube setting-up device wherein an identification label can be pasted over a product label with a simple structure. A labeling device for an automatic blood-sampling-tube setting-up device comprises a means for taking out a blood-sampling tube based on patient information and supporting the blood-sampling tube at a labeling position, a blood-sampling tube driving means for rotary driving the blood-sampling tube at the labeling position, a label printing means for creating an identification label by printing test information and/or patient information and outputting the identification label to the labeling position, a product label position detecting means for detecting the edge of a product label previously pasted to the outer surface of the blood-sampling tube, and a controller for controlling the operation of the label printing means and the blood-sampling tube driving means such that the identification label is pasted over the product label with a continuous gap left in the axial direction of the blood-sampling tube on the outer surface of a blood-sampling tube based on information about the diameter of a blood-sampling tube corresponding to the blood-sampling tube at the labeling position, and information about the edge of the product label obtained from the product label position detecting means.