A treatment system (10; 310) configured to apply energy to living tissues to treat the living tissues, the treatment system (10; 310) comprising: a pair of holding members (62, 64; 342, 344), each having a holding surface (72b, 82b; 384, 388, 434, 438) configured to hold the living tissues and J a cutter guide groove (62a, 64a; 362, 426) configured to guide a cutter (54; 364) to cut the living tissues inside and outside with respect to the holding surface; a sealing member (76, 86; 372, 422) which includes first and second continuous electrodes, which are provided without discontinuity on the respective holding surface surrounding the respective cutter guide groove and which are configured to join desired regions of the living tissues when a high frequency energy or thermal energy is applied to the living tissues arranged between the first and second electrodes; a maintaining member (78, 88; 374, 424) which includes first and second pluralities of discrete electrodes, which are configured to maintain joining by discontinuous joining the living tissues when the high frequency energy or the thermal energy is applied to the living tissues near the region sealed by the sealing member, wherein the living tissues are arranged between the first and second pluralities of discrete electrodes; a first output circuit which is configured to switch supplying and non-supplying of the high frequency energy or the thermal energy to the sealing member, depending on a first impedance of the living tissues between the first and second electrodes of the sealing member, obtained with supplying the high frequency energy or the thermal energy to the sealing member; a second output circuit which is configured to switch supplying and non-supplying of the high frequency energy or the thermal energy to the maintaining member, depending on a second impedance of the living tissues between the first and second pluralities of discrete electrodes of the maintaining member, obtained with supplying the high frequency energy or the thermal energy to the maintaining member; a display section configured to permit the selection of a first threshold value for the first impedance and a second threshold value for the second impedance; a switch; and a control section which is configured to control the first output circuit and the second output circuit, to simultaneously supply energy to the sealing member and the maintaining member when the switch is turned on, to control the supply of the high frequency energy or the thermal energy from the first output circuit and the second output circuit, to stop the output from the first output circuit when the first impedance reaches the first threshold value, and to stop the output from the second output circuit when the second impedance reaches the second threshold value. a pair of holding members (62, 64; 342, 344), each having a holding surface (72b, 82b; 384, 388, 434, 438) configured to hold the living tissues and J a cutter guide groove (62a, 64a; 362, 426) configured to guide a cutter (54; 364) to cut the living tissues inside and outside with respect to the holding surface; a sealing member (76, 86; 372, 422) which includes first and second continuous electrodes, which are provided without discontinuity on the respective holding surface surrounding the respective cutter guide groove and which are configured to join desired regions of the living tissues when a high frequency energy or thermal energy is applied to the living tissues arranged between the first and second electrodes; a maintaining member (78, 88; 374, 424) which includes first and second pluralities of discrete electrodes, which are configured to maintain joining by discontinuous joining the living tissues when the high frequency energy or the thermal energy is applied to the living tissues near the region sealed by the sealing member, wherein the living tissues are arranged between the first and second pluralities of discrete electrodes; a first output circuit which is configured to switch supplying and non-supplying of the high frequency energy or the thermal energy to the sealing member, depending on a first impedance of the living tissues between the first and second electrodes of the sealing member, obtained with supplying the high frequency energy or the thermal energy to the sealing member; a second output circuit which is configured to switch supplying and non-supplying of the high frequency energy or the thermal energy to the maintaining member, depending on a second impedance of the living tissues between the first and second pluralities of discrete electrodes of the maintaining member, obtained with supplying the high frequency energy or the thermal energy to the maintaining member; a display section configured to permit the selection of a first threshold value for the first impedance and a second threshold value for the second impedance; a switch; and a control section which is configured to control the first output circuit and the second output circuit, to simultaneously supply energy to the sealing member and the maintaining member when the switch is turned on, to control the supply of the high frequency energy or the thermal energy from the first output circuit and