The present invention provides a system having: packages (2) of shuffled playing cards (1s) in which playing cards included are shuffled in random order and are individually packed in one package (2), and in which a unique ID code (4) is attached to each unique package (2); a game table (11); a storage box (401) that is installed beside the game table (11), stores the plurality of packages (2), includes a reader (451) that reads the ID codes (4) of all the packages (2), and includes an openable lid (452a, 452b) so that the packages can be taken out one by one; and a control device (112) for monitoring whether or not the packages (2) are present in the storage box (401) by monitoring the ID codes (4) of the packages (2) read by the readers (451), and for outputting monitoring results.