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.(I)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-P2wherein each symbol is as defined herein.