Provided is a printing and thermal activation device for a heat-sensitive adhesive sheet that is compact, lightweight, and simple in structure. The heat-sensitive adhesive device for a heat-sensitive adhesive sheet includes a thermal head capable of printing on a printable layer and thermal activation for a heat-sensitive adhesive layer. When the heat-sensitive adhesive sheet is inserted, a platen roller and the thermal head are operated to transport the heat-sensitive adhesive sheet while printing on the printable layer. The heat-sensitive adhesive sheet is cut with a cutter unit at a predetermined position and then the cut sheet passes through a transporting roller pair and is guided to a reversing mechanism. The heat-sensitive adhesive sheet makes almost one rotation on an outer periphery of a reversing roller and is reversed, and then is transported by the transporting roller pair and the platen roller starting reverse rotation while the heat-sensitive adhesive layer is thermally activated with the thermal head.