A peptide having any one of the amino acid sequences of SEQ ID NO: 1 or 13, preferably a peptide having any one of the amino acid sequences of SEQ ID NOS: 2 to 9 or a peptide having any one of the amino acid sequences of SEQ ID NOS: 10 and 15 to 17, is used as an active ingredient of an agent for promoting growth or differentiation of cells such as osteoblasts, chondroblasts, cementoblasts, bone marrow-derived mesenchymal stem cells and periodontal ligament-derived cells.