There is provided a shuffled playing card, wherein a suit and a rank are printed on one surface of a card base sheet, and a back pattern is printed on another surface, different sheet IDs for one card base sheet or each of a plurality of card base sheets are printed on the card base sheet, one deck or a plurality of decks are formed by individual cards cut by a cutting machine from the card base sheet, the one deck or the plurality of decks are shuffled by a shuffle machine to form a set of shuffled playing cards, different shuffled playing card IDs for each set are assigned to the shuffled playing card as ID codes, and the sheet ID of the playing card constituting the shuffled playing card and the shuffled playing card ID are associated with each other in a database.