A banknote separating device, comprising: a supporting side plate and an impeller wheel assembly, a banknote separating assembly, a first banknote pressing assembly and a second banknote pressing assembly, which are mounted to the supporting side plate, wherein the first banknote pressing assembly comprises a first banknote pressing plate and a synchronous belt pulley mechanism configured to drive the first banknote pressing plate, the synchronous belt pulley mechanism comprises two synchronous pulleys and a synchronous belt sleeved on the synchronous pulleys, one of the synchronous pulleys is mounted at one end of a rotatable plate by a first riveting shaft, another end of the rotatable plate is mounted on the supporting side plate by a second riveting shaft, and the rotatable plate is rotatable about the second riveting shaft; each of the supporting side plate and the rotatable plate comprises a sliding slot, the first banknote pressing plate is mounted in the sliding slot of the rotatable plate via a bearing and extends into the sliding slot of the supporting side plate, and the first banknote pressing plate is connected to the synchronous belt via a belt connecting plate and moves forward and backward in the sliding slot of the rotatable plate with rotating of the synchronous belt; and the second banknote pressing assembly comprises a second banknote pressing plate and a crank-rocker mechanism configured to drive the second banknote pressing plate, and the crank-rocker mechanism comprises: a direct current motor fixed to the supporting side plate, a crank fixed to a motor shaft of the direct current motor, a connecting rod connected to the crank, and a rocker connected to the connecting rod, with another end of the rocker fixed to a shaft; and the second banknote pressing plate is also fixed to the shaft by a banknote pressing bracket. a supporting side plate and an impeller wheel assembly, a banknote separating assembly, a first banknote pressing assembly and a second banknote pressing assembly, which are mounted to the supporting side plate, wherein the first banknote pressing assembly comprises a first banknote pressing plate and a synchronous belt pulley mechanism configured to drive the first banknote pressing plate, the synchronous belt pulley mechanism comprises two synchronous pulleys and a synchronous belt sleeved on the synchronous pulleys, one of the synchronous pulleys is mounted at one end of a rotatable plate by a first riveting shaft, another end of the rotatable plate is mounted on the supporting side plate by a second riveting shaft, and the rotatable plate is rotatable about the second riveting shaft; each of the supporting side plate and the rotatable plate comprises a sliding slot, the first banknote pressing plate is mounted in the sliding slot of the rotatable plate via a bearing and extends into the sliding slot of the supporting side plate, and the first banknote pressing plate is connected to the synchronous belt via a belt connecting plate and moves forward and backward in the sliding slot of the rotatable plate with rotating of the synchronous belt; and the second banknote pressing assembly comprises a second banknote pressing plate and a crank-rocker mechanism configured to drive the second banknote pressing plate, and the crank-rocker mechanism comprises: a direct current motor fixed to the supporting side plate, a crank fixed to a motor shaft of the direct current motor, a connecting rod connected to the crank, and a rocker connected to the connecting rod, with another end of the rocker fixed to a shaft; and the second banknote pressing plate is also fixed to the shaft by a banknote pressing bracket. a direct current motor fixed to the supporting side plate, a crank fixed to a motor shaft of the direct current motor, a connecting rod connected to the crank, and a rocker connected to the connecting rod, with another end of the rocker fixed to a shaft; and the second banknote pressing plate is also fixed to the shaft by a banknote pressing bracket.