Abstract: One of the purposes of the present invention is to provide a method for producing a gene-edited tissue stem cell in an undifferentiated state within a short period of time. Another one of the purposes of the present invention is to provide a method for treating and/or preventing a disease using a gene-edited tissue stem cell in an undifferentiated state. A gene-edited tissue stem cell is produced by a method comprising a step for editing the gene sequence of a target gene in tissue stem cells, and a step for selecting the tissue stem cells having an edited gene sequence, and optionally, further comprising a step for adding a tag to the gene sequence of the target gene and/or a step for activating gene expression of the target gene in the tissue stem cells. The tissue stem cell thus produced is used in treating/preventing diseases.