A banknote processing device, comprising: an identification mechanism, an in-out mechanism, a loading box, a circulating box, a main passage, an auxiliary passage, an in-out passage, a loading passage, and a circulating passage; wherein the auxiliary passage is of an annular shape, and both ends of the main passage are connected to the auxiliary passage respectively, wherein a banknote is allowed to move in a one-way direction along a preset direction in the auxiliary passage; the identification mechanism is arranged in the main passage; the in-out passage is connected between the main passage and the in-out mechanism; a first end of the circulating passage is connected to the main passage, and a second end of the circulating passage is in communication with the circulating box; and a first end of the loading passage is connected to the auxiliary passage, and a second end of the loading passage is connected to the loading box; wherein the auxiliary passage comprises a first passage, a second passage, and a third passage, wherein the first passage, the second passage, and the third passage are annularly distributed; wherein a first end of the first passage, a second end of the third passage, and a second end of the main passage intersect with each other; a second end of the first passage, a first end of the second passage, and the first end of the loading passage intersect with each other; and a second end of the second passage, a first end of the third passage, and a first end of the main passage intersect with each other; the banknote processing device comprises a recycling passage and a recycling box; wherein a first end of the recycling passage is connected to the auxiliary passage, and a second end of the recycling passage is connected to the recycling box; wherein the in-out mechanism comprises an inlet and an outlet, wherein the in-out passage comprises a banknote incoming path and a banknote outgoing path, wherein the inlet is connected to the main passage through the banknote incoming path; and the outlet is connected to the main passage through the banknote outgoing path; and wherein junction of the banknote incoming path and the main passage is located between the first end of the main passage and the identification mechanism, and a junction of the banknote outgoing path and the main passage is located between the second end of the main passage and the identification mechanism. wherein the auxiliary passage is of an annular shape, and both ends of the main passage are connected to the auxiliary passage respectively, wherein a banknote is allowed to move in a one-way direction along a preset direction in the auxiliary passage; the identification mechanism is arranged in the main passage; the in-out passage is connected between the main passage and the in-out mechanism; a first end of the circulating passage is connected to the main passage, and a second end of the circulating passage is in communication with the circulating box; and a first end of the loading passage is connected to the auxiliary passage, and a second end of the loading passage is connected to the loading box; wherein the auxiliary passage comprises a first passage, a second passage, and a third passage, wherein the first passage, the second passage, and the third passage are annularly distributed; wherein a first end of the first passage, a second end of the third passage, and a second end of the main passage intersect with each other; a second end of the first passage, a first end of the second passage, and the first end of the loading passage intersect with each other; and a second end of the second passage, a first end of the third passage, and a first end of the main passage intersect with each other; the banknote processing device comprises a recycling passage and a recycling box; wherein a first end of the recycling passage is connected to the auxiliary passage, and a second end of the recycling passage is connected to the recycling box; wherein the in-out mechanism comprises an inlet and an outlet, wherein the in-out passage comprises a banknote incoming path and a banknote outgoing path, wherein the inlet is connected to the main passage through the banknote incoming path; and the outlet is connected to the main passage through the banknote outgoing path; and wherein junction of the banknote incoming path and the main passage is located between the first end of the main passage and the identification mechanism, and a junction of the banknote outgoing path and the main passage is located between the second end of the main passage and the identification mechanism.