An objective of the present invention is to provide vectors for conveniently and efficiently producing ES-like cells in which foreign genes are not integrated into the chromosome. The present inventors discovered methods for producing ES-like cells from somatic cells using chromosomally non-integrating viral vectors. Since no foreign gene is integrated into the chromosome of the produced ES-like cells, they are advantageous in tests and research, and immunological rejection and ethical problems can be avoided in disease treatments.
