The present invention relates to a multi-stage isolator. The multi-stage isolator according to the present invention includes an isolator main body that is sealed by a removable observation door, has isolators having inner spaces disposed to be stackable, and removes a pollution source by air supply and exhaust of the respective inner spaces of the isolators in accordance with control by a controller； a pair of pass boxes that are disposed on one side of the isolator to be connected to the inner spaces of the isolators and carry in or out experimental birds or store experimental equipment； a pair of gloves that are disposed at the observation door of the isolator to be connected to the inner space of the isolators and safely capture or test the experimental birds； and a pair of excreta trays that are disposed on a bottom of the isolator to be connected to the inner spaces of the isolators and collect excreta of the experimental birds. The excreta tray is disposed in an in-out tray that has a space for excreta tray insertion therein and has roll-type synthetic resin inserted into an outer circumferential surface so that pollution expansion attributable to excreta tray take-out can be prevented. According to the present invention, the synthetic resin inserted in a roll shape into the outer circumferential surface of the in-out tray performs sealing during excreta tray collection through the in-out tray into which the excreta tray is inserted, and thus pollution source expansion attributable to the excreta tray can be prevented. In addition, impairment of the glove due to the experimental birds can be prevented by a glove shutter.본 발명은 다단형 무균함에 관한 것이다.본 발명의 다단형 무균함은 탈착 가능한 관찰도어로 밀폐되어 내부공간을 갖는 무균함들이 적층 가능하게 설치되되, 그 무균함들의 각 내부공간을 콘트롤러의 제어에 따라 급·배기하여 오염원을 제거하도록 한 무균함본체； 상기 무균함들의 내부공간과 연결되게 무균함의 일측에 설치되어 실험조류를 반입·반출하거나 실험기자재를 보관하도록 한 한 쌍의 패스박스들； 상기 무균함들의 내부공간과 연결되게 무균함의 관찰도어에 설치되어 실험조류를 안전하게 포획하거나 실험하도록 한 한 쌍의 글로브들； 및 상기 무균함들의 내부공간과 연결되게 무균함의 바닥에 설치되어 실험조류로부터 발생되는 분뇨가 수거
