A printer selectively prints on heat-sensitive adhesive sheets and ordinary sheets that have no heat-sensitive adhesive. The printer has a printing unit that prints on one surface of a sheet and a printing platen roller that transports the sheet in a forward direction. A cutter unit cuts the printed sheet to a predetermined length, and a thermal activation unit disposed downstream of the cutter unit has a thermal head for heating the other surface of the sheet and a thermal activation platen roller that transports the sheet in the forward direction. A detector detects whether the sheet is a heat-sensitive adhesive sheet or an ordinary sheet, and a control device controls operation of the thermal activation unit so that both the thermal head and the thermal activation platen roller are operated in response to detection of a heat-sensitive adhesive sheet and so that the thermal activation platen roller but not the thermal head is operated in response to detection of an ordinary sheet.