An electro-surgical device (12 12a 12b 12c) for joining living tissues, includes a pair of holding faces (54a, 54b), a joining treatment portion (54a, 54b), and a fluid feed portion (56a, 56b). The pair of holding faces (54a, 54b) hold the living tissues. The joining treatment portion (54a, 54b) is arranged in at least one of the pair of holding faces to join the living tissues held between the pair of holding faces by energy supplied from an energy source. The fluid feed portion (56a, 56b) is provided on the holding face or the joining treatment portion, and is able to feed a conductive fluid to the living tissues held by the pair of holding faces.