Provided are a stem cell preservation medium, stem cell preservation method and stem cell preservation system which can be used in a slow-freezing method that is used in place of vitrification, have a high cell survival rate and are convenient and highly efficient. The stem cell preservation medium comprises hydroxyethyl starch (HES), dimethyl sulfoxide (DMSO), and ethylene glycol (EG). The stem cell preservation method comprises: a dissociation step in which stem cells are dissociated using a pronase solution； and a freezing step in which the dissociated stem cells are slow-frozen in the stem cell preservation medium. The stem cell preservation system comprises: the pronase solution which is a dissociation means for dissociating stem cells； the stem cell preservation medium according to the present invention； and a slow-freezing means with which the dissociated stem cells are slow-frozen in the stem cell preservation medium.
