A device for washing and dewatering a fiber pulp suspension. The external storage device comprises a first connection unit having a first input port and a first output port, and a second connection unit having a second output port and a second input port that are connected to a first input port and a first output port of an adjacent external storage device on the first route, respectively, to form one communication channel of the first route. to asymmetric reduction in the presence of an optically active oxazaborolidine compound and a boron hydride compound, or in the presence of an asymmetric transition metal complex obtained from a transition metal compound and an asymmetric ligand and a hydrogen donor, and relates to said compound. Each channelgate insulating film 14a is formed between each channel region 23 and its corresponding floating gate electrode 24.