To provide a breeding device having water purification function sufficient even when improving a breeding density of aquatic lives.SOLUTION: A breeding device 100 includes a first filtration device 2 having a separation membrane, for obtaining concentrated water and permeated water by filtering water extracted from a breeding tank 1 by the separation membrane, a biological treatment device 3 for biologically treating a material contained in the permeated water obtained in the first filtration device 2, and a reflux part for returning water treated in the biological treatment device 3 into the breeding tank.SELECTED DRAWING: Figure 1【課題】水中生物の飼育密度を向上させても十分な水の浄化機能を有する飼育装置を提供する。【解決手段】飼育装置１００は、分離膜を有し、飼育槽１から抜き出された水を分離膜でろ過することで濃縮水と透過水を得る第１ろ過装置２と、前記第１ろ過装置２で得られた透過水に含まれる物質を生物処理する生物処理装置３と、前記生物処理装置３で処理された水を前記飼育槽に戻す還流部とを備える。【選択図】図１
