The present invention relates to a peptide compound that may be useful in the treatment or prophylaxis of obesity, diabetes and the like. More specifically, the present invention relates to a peptide compound represented by the formula (I) : P 1 -Tyr-Aib-Glu-Gly-Thr-?MePhe-Thr-Ser-Asp-Lys(-Gly-Gly-Gly-Gly-R A10 )-A11-A12-Aib-Leu-A15-Lys-Gln-A18-Gln-Iva-Glu-Phe-Val-Arg-His-Leu-Leu-Asn-Lys-Aib-Thr-Arg-Gln-Arg-A35-NH 2 wherein each symbol is as defined in the specification, and the treatment or prophylaxis of obesity, diabetes and the like using the peptide compound.