A surgical sealant consisting of (1) a first agent comprising a gelatin derivative, wherein the gelatin derivative (a) has a weight average molecular weight of from 10,000 to 50,000； (b) has a hydrophobic group bonded thereto, the hydrophobic group being an alkyl group having 6 to 18 carbon atoms； (c) has a molar ratio of imino group/amino group of the gelatin derivative ranging from 1/99 to 30/70； and (d) comprises a structure represented by the following formula: GltnNH—；CHR1R2, wherein “Gltn” represents a gelatin residue, R1 is the hydrophobic group, and R2 is a hydrogen atom or the hydrophobic group； and (2) a second agent comprising a crosslinking agent for the gelatin derivative.
