A medical treatment device (12) configured to treat body tissues (L1, L2) for conjugation includes a pair of holding members (52, 54) to hold the body tissues, an energy output portion (92, 94) provided in at least one of the holding members to join the body tissues by supplying energy to the body tissues, and a conjugation coating portion (262) to coat contact surfaces (C1, C2) of the body tissues with a substance capable of preventing fluid from invading.
