There is provided a novel adrenomedullin derivative capable of sustainably acting for a longer period than natural adrenomedullin. The invention relates to a compound represented by formula (I): A-Ln-B (I), wherein A is a modifying group selected from the group consisting of a palmitoyl group and a polyethylene glycol group, L is a divalent linking group, n is an integer of 0 or 1, and B is a peptide moiety derived from adrenomedullin or a modified form thereof with adrenomedullin activity, wherein the peptide moiety B is bound to the modifying group A or the linking group L via the N-terminal amino group of the peptide moiety B, or a salt thereof, or a hydrate thereof.