The vitrification medium for cells according to the present invention is a vitrification medium for cells comprising a cell membrane permeable substance and a cell membrane non-permeable substance, in which, the content of the cell membrane permeable substance is in the range of 30 to 50% by volume, and the osmotic pressure generated in association with the cell membrane non-permeable substance, which is a fraction of the total osmotic pressure on the cell membrane on suspending the cells in the vitrification medium, is in the range of 280 mOsm or more. The vitrification medium for cells according to the present invention is excellent in operability and safety.
