A process for producing a stem cell, the process comprising the step of culturing the stem cell in the presence of: (a) a recombinant polypeptide comprising human fibronectin III-1 to 3 repeats or III-4 to 6 repeats in the order of the repeats III-1, 2, and 3 or III-4, 5 and 6 from N- to C-terminal, or a recombinant polypeptide comprising an amino acid sequence having substitution, deletion, insertion or addition of one or 1 to 10 amino acids in the amino acid sequences of III-1 to 3 repeats or III-4 to 6 repeats in the order of the repeats III-1, 2 and 3 or III-4,5 and 6 from N- to C-terminal, wherein III-1 to 3 repeats are set forth in SEQ ID NO: 1 to 3, respectively or III-4 to 6 repeats are set forth in SEQ ID NO: 4 to 6, respectively; (b) a recombinant polypeptide comprising human fibronectin III-8 to 10 repeats in the order of the repeats III-8, 9 and 10 from N- to C-terminal, or a recombinant polypeptide comprising an amino acid sequence having substitution, deletion, insertion or addition of one or 1 to 10 amino acids in the amino acid sequence of the III-8 to 10 repeats in the order of the repeats III-8, 9 and 10 from N- to C-terminal, wherein III-8 to 10 repeats are set forth in SEQ ID NO: 8 to 10, respectively; and (c) a recombinant polypeptide comprising human fibronectin III-12 to 14 repeats in the order of the repeats III-12, 13 and 14 from N- to C-terminal, or a recombinant polypeptide comprising an amino acid sequence having substitution, deletion, insertion or addition of one or 1 to 10 amino acids in the amino acid sequence of the III-12 to 14 repeats in the order of the repeats III-12, 13 and 14 from N- to C-terminal, wherein III-12 to 14 repeats are set forth in SEQ ID NO: 12 to 14, respectively; wherein the recombinant polypeptides (a), (b), and (c) comprising an amino acid sequence having substitution, deletion, insertion or addition of one or 1 to 10 amino acids are functionally equivalent to a corresponding polypeptide into which no amino acid substitution, deletion, insertion nor addition has been introduced and retain a function of making stem cells proliferate, a function of maintaining an undifferentiated state of stem cells, or a function of inducing stem cells, and wherein the recombinant polypeptides (a), (b), and (c) are not full-length human fibronectin, and wherein if the recombinant polypeptides (a), (b), and (c) are included in the same molecule, they are arranged in the order of the polypeptides (a), (b), and (c) from N- to C-terminal. (a) a recombinant polypeptide comprising human fibronectin III-1 to 3 repeats or III-4 to 6 repeats in the order of the repeats III-1, 2, and 3 or III-4, 5 and 6 from N- to C-terminal, or a recombinant polypeptide comprising an amino acid sequence having substitution, deletion, insertion or addition of one or 1 to 10 amino acids in the amino acid sequences of III-1 to 3 repeats or III-4 to 6 repeats in the order of the repeats III-1, 2 and 3 or III-4,5 and 6 from N- to C-terminal, wherein III-1 to 3 repeats are set forth in SEQ ID NO: 1 to 3, respectively or III-4 to 6 repeats are set forth in SEQ ID NO: 4 to 6, respectively; (b) a recombinant polypeptide comprising human fibronectin III-8 to 10 repeats in the order of the repeats III-8, 9 and 10 from N- to C-terminal, or a recombinant polypeptide comprising an amino acid sequence having substitution, deletion, insertion or addition of one or 1 to 10 amino acids in the amino acid sequence of the III-8 to 10 repeats in the order of the repeats III-8, 9 and 10 from N- to C-terminal, wherein III-8 to 10 repeats are set forth in SEQ ID NO: 8 to 10, respectively; and (c) a recombinant polypeptide comprising human fibronectin III-12 to 14 repeats in the order of the repeats III-12, 13 and 14 from N- to C-terminal, or a recombinant polypeptide comprising an amino acid sequence having substitution, deletion, insertion or addition of one or 1 to 10 amino acids in the amino acid sequence of the III-12 to 14 repeats in the order of the repeats III-12, 13 and 14 from N- to C-terminal, wherein III-12 to 14 repeats are set forth in SEQ ID NO: 12 to 14, respectively; wherein the recombinant polypeptides (a), (b), and (c) comprising an amino acid sequence having substitution, deletion, insertion or addition of one or 1 to 10 amino acids are functionally equivalent to a corresponding polypeptide into which no amino acid substitution, deletion, insertion nor addition has been introduced and retain a function of making stem cells proliferate, a function of maintaining an undifferentiated state of stem cells, or a function of inducing stem cells, and wherein the recombinant polypeptides (a), (b), and (c) are not full-length human fibronectin, and wherein if the recombinant polypeptides (a), (b), and (c) are included in the same molecule, they are arranged in the order of the polypeptides (a), (b), and (c) from N- to C-terminal.