A method for collecting cells that have been cultured by using a cell culture kit in which, at least, a culture container for cultivating cells, a cell collection container for collecting cells after cultivation and a waste liquid container for collecting a culture medium after cultivation are linked to one another through a conduit is provided. The method includes transferring a culture supernatant that has been cultured from the culture container to the waste liquid container, transferring a concentrated suspension of cells from the culture container to the cell collection container, returning part of the culture supernatant discharged in the waste liquid container to the culture container and allowing cells remaining in the culture container to be suspended in a suspension of cells, and transferring again a suspension of cells in which remaining cells are suspended from the culture container to the cell collection container.