[Problem] To assist a doctor in determining a region to be resected when conducting ablative surgery on a tubular organ. [Solution] Provided is a surgical assistance device (3) equipped with: an organ region extraction unit (33) that extracts a tubular organ region (C) from a three-dimensional image (D) obtained by imaging a tubular organ and blood vessels that control the tubular organ a blood vessel region extraction unit (35) that extracts a blood vessel region (V) that controls the tubular organ (C) from the three-dimensional image (D) a branching structure extraction unit (36) that extracts branching structures (S) of blood vessels from the extracted blood vessel region (V) and a controlled region identification unit (37) which, on the basis of arbitrarily-defined partial blood vessels corresponding to one or more upper branches from branches containing terminals of the extracted branching structures (S), uses positional relationships between the tubular organ region (C) and a plurality of end points at final branch destinations from the branches of the partial blood vessels to identify a controlled region (FC) controlled by the partial blood vessels in the tubular organ region (C).La présente invention vise à aider un médecin à déterminer une région à enlever lors de la réalisation dune chirurgie dablation sur un organe tubulaire. A cet effet, linvention concerne un dispositif dassistance chirurgicale (3) qui comprend : une unité dextraction de région dorgane (33) qui extrait une région dorgane tubulaire (C) dune image tridimensionnelle (D) obtenue par imagerie dun organe tubulaire et de vaisseaux sanguins qui contrôlent lorgane tubulaire une unité dextraction de région de vaisseaux sanguins (35) qui extrait de limage tridimensionnelle (D) une région de vaisseaux sanguins (V) qui contrôle lorgane tubulaire (C) une unité dextraction de structures de ramification (36) qui extrait de la région de vaisseaux sanguins (V) extraite des structures de ramification (S
