The present invention provides a novel peptide compound having an activating action on GIP receptors and use of the peptide compound as a medicament. Specifically, a peptide containing a sequence represented by the formula (I) or a salt thereof and a medicament comprising the same are provided. P1-Tyr-A2-Glu-Gly-Thr-A6-A7-A8-A9-A10-A11-A12-A13-A14-A15-A16-A17-A18-A19-A20-A21-A22-A23-A24-A25-A26-A27-A28-A29-A30-A31-A32-A33-A34-A35-A36-A37-A38-A39-A40-P2 (I) wherein each symbol is as defined herein.本發明係提供一種對GIP受體具有活化作用之新穎胜肽化合物及該胜肽化合物作為藥劑之用途。詳細而言,係提供一種含有式(I)表示之序列之胜肽或其鹽,以及包含該胜肽或其鹽之藥劑。P1-Tyr-A2-Glu-Gly-Thr-A6-A7-A8-A9-A10-A11-A12-A13-A14-A15-A16-A17-A18-A19-A20-A21-A22-A23-A24-A25-A26-A27-A28-A29-A30-A31-A32-A33-A34-A35-A36-A37-A38-A39-A40-P2 (I)其中,每一符號係定義於本文中。