The invention discloses a floating mechanism of a currency detection apparatus and a currency detection apparatus. The floating mechanism includes a rack (1), two shrapnels (2) and a floating shaft (3). The left and right ends of the floating shaft (3) are separately sleeved with a flange bearing (4). The rack (1) includes two supporting plates (11) which are parallel to each other and a fixing plate (12) which is disposed between the two supporting plates (11). The left end of the floating shaft (3) is installed on the corresponding supporting plate (11) through the corresponding flange bearing (4). One end of respective shrapnel (2) is fixed on the fixing plate (12), and the other end of respective shrapnel (2) abuts against one side of the corresponding flange bearing (4) approaching the fixing plate (12). The floating mechanism can work normally and stably. The currency detection apparatus includes a magnetic sensor (5) and the aforementioned floating mechanism. The floating shaft (3) is sleeved with a floating roller (6). One end of the floating shaft (3) is provided with a transmission belt pulley (7). The currency detection can acquire magnetic data of paper currency in a stable and reliable manner.