The present invention provides a closed ultra-fast device for vitrification that reduces the risk of contamination; favors and increases the survival of human cells (e.g., oocytes, embryos, sperm, etc.) or non-human cells after thawing; and achieves ultra-fast cooling rates with a low concentration of cryo-protectors. The device of the present invention avoids risk of contamination, favors and increases the survival rate of human (oocytes, embryos or sperm, etc) or nonhuman cells after thawing, featuring ultra-rapid cooling rates and the use of low concentrations of cryo-protectors. The device comprises a protective sheath made of an inert, flexible and transparent material, inside of which a micro-capillary, preferably of quartz, is intended to house the cells that are to be vitrified. The protective sheath is adapted to be protectively sealed at its superior extremity, thereby creating a hermetic seal of the device and preventing the entry of coolant (liquid nitrogen, slush or slurry) into the protective sheath.