A banknote handling system comprising: a reception unit configured to receive a banknote that has been put therein; a recognition unit configured to recognize the banknote that has been received by the reception unit; a storing unit having at least one first cassette configured to escrow the banknote that has been recognized by the recognition unit and to feed out therefrom the banknote that has been escrowed therein, and at least one second cassette (132A-132C) configured to store the banknote that has been recognized by the recognition unit and to feed out therefrom the banknote that has been stored therein; a transport path provided between the first cassette and the second cassette (132A-132C); a transport-error detection unit configured to detect a transport error of a banknote on the transport path; and a control unit configured to control the second cassette (132A-132C) so as to feed out all the banknotes stored therein to the transport path; to cause all the banknotes fed out from the second cassette (132A-132C) without a transport error to be escrowed in the first cassette if the transport-error detection unit of the transport path does not detect a transport error, to control the first cassette so as to feed out the banknote escrowed therein, to cause the number of banknotes of each denomination to be recognized by the recognition unit; to compare amount-of money data of the banknotes stored in the storing unit with the number of banknotes of each denomination recognized by the recognition unit to produce a comparison result, and to cause the banknote to be stored again in the second cassette (132A-132C). a reception unit configured to receive a banknote that has been put therein; a recognition unit configured to recognize the banknote that has been received by the reception unit; a storing unit having at least one first cassette configured to escrow the banknote that has been recognized by the recognition unit and to feed out therefrom the banknote that has been escrowed therein, and at least one second cassette (132A-132C) configured to store the banknote that has been recognized by the recognition unit and to feed out therefrom the banknote that has been stored therein; a transport path provided between the first cassette and the second cassette (132A-132C); a transport-error detection unit configured to detect a transport error of a banknote on the transport path; and a control unit configured to control the second cassette (132A-132C) so as to feed out all the banknotes stored therein to the transport path; to cause all the banknotes fed out from the second cassette (132A-132C) without a transport error to be escrowed in the first cassette if the transport-error detection unit of the transport path does not detect a transport error, to control the first cassette so as to feed out the banknote escrowed therein, to cause the number of banknotes of each denomination to be recognized by the recognition unit; to compare amount-of money data of the banknotes stored in the storing unit with the number of banknotes of each denomination recognized by the recognition unit to produce a comparison result, and to cause the banknote to be stored again in the second cassette (132A-132C).