The purpose of the present invention is to obtain a cell suspension with a low concentration of cryoprotectant. This method of preserving cells used comprises the steps of (a) enriching cells from a cell suspension containing the cells and a cryoprotective solution to generate an enriched fraction, and (b) freezing the enriched fraction to prepare a frozen material. It is also possible to use a method of producing a cell suspension, comprising the steps of (a) enriching cells from a cell suspension containing the cells and a cryoprotective solution to generate an enriched fraction, (b) freezing the enriched fraction to prepare a frozen material, (c) thawing the frozen material to prepare a thawed material, and (d) mixing the thawed material and a solution to produce a cell suspension.