Abstract: A close-system cell isolation device includes a first culture bag, a second culture bag, immunomagnetic beads, and a connecting tube. The first culture bag and the second culture bag are closely connected with each other through the connecting tube. The first culture bag has the immunomagnetic beads and cells. When the first culture bag is forced by a magnetic force and an external force, the cells uncaptured by the immunomagnetic beads are moved from the first culture bag to the second culture bag through the connecting tube by the external force, and the cells captured by the immunomagnetic beads are retained in the first culture bag by the magnetic force. Accordingly, the cell isolation can be performed without contamination.