PROBLEM TO BE SOLVED: To provide a binding material specific to IGF-1R with high affinity and a medicine containing the same.SOLUTION: Disclosed is a peptide with 8-50 amino acids, having an amino acid sequence expressed by at least a following formula (1), wherein, Xis Tyr, Trp, Phe, or His, Xis Ser, Ala, Thr, Gly, Asn, Asp, Glu, Arg, or Lys, Xis Met, Leu, Ile, Val, Ala, Phe, Tyr, Trp, or Cys, Xis Leu, Ile, Val, or Met, Xis Gln, Asn, Asp, Glu, Ala, Ser, Thr, Leu, Met, Lys, or Arg, Xis Arg, Lys, His, Asn, Gln, Ser, Thr, Asp, Glu, or Ala, and Xis Leu, Ile, Val, or Met.【課題】IGF-1Rに特異的かつ高親和性で結合する物質及びそれを含む医薬を提供する。【解決手段】少なくとも下記式(1)で表されるアミノ酸配列を有するアミノ酸数8～50のペプチド。（式中、X1はTyr、Trp、Phe又はHisを示し、X2はSer、Ala、Thr、Gly、Asn、Asp、Glu、Arg又はLysを示し、X3はMet、Leu、Ile、Val、Ala、Phe、Tyr、Trp又はCysを示し、X4はLeu、Ile、Val又はMetを示し、X5はGln、Asn、Asp、Glu、Ala、Ser、Thr、Leu、Met、Lys又はArgを示し、X6はArg、Lys、His、Asn、Gln、Ser、Thr、Asp、Glu又はAlaを示し、X7はLeu、Ile、Val又はMetを示す）【選択図】なし
