In order to provide a novel peptide having both an osteogenesis promoting action and a chondrocyte proliferation promoting action, the present invention comprises the following amino acid sequence (a), (b) or (c), and has 100 amino acid residues. A peptide or derivative thereof or a salt thereof having the following activity of promoting osteoblast proliferation is provided. (A) Val-Asn-Pro-Glu-Ser-Glu-Glu-Glu-Asp-Glu-Ser-Ser-Pro-Tyr-Glu (SEQ ID NO: 1) (b) 1 to 3 in the amino acid sequence of (a) An amino acid sequence comprising at least four consecutive amino acids in the amino acid sequence (c) (a) or (b) having a conservative substitution or deletion of one amino acid本発明は、骨形成促進作用と軟骨細胞増殖促進作用を併せ持つ新規なペプチドを提供するために、以下の(a)、(b)または(c)のアミノ酸配列を含み、アミノ酸残基数が100以下であり、骨芽細胞増殖促進活性を有するペプチドもしくはその誘導体またはその塩を提供する。(a)Val-Asn-Pro-Glu-Ser-Glu-Glu-Glu-Asp-Glu-Ser-Ser-Pro-Tyr-Glu(配列番号1)(b)(a)のアミノ酸配列において1~3個のアミノ酸の保存的置換または欠失を有するアミノ酸配列(c)(a)または(b)のアミノ酸配列において少なくとも4つの連続するアミノ酸からなるアミノ酸配列