The invention provides a surgical tool in which the tension of a connector that connects a holder assembly for holding tissues to a main unit is so adjusted that a tissue can be unerringly held with application of unerring treatment and which can avoid interference with other surgical tools. The surgical tool (1) is including a main unit (2) including a case (21) and a hollow shaft (22) provided on the case (21), a holder assembly (3) that holds a living tissue (T) in the body cavity, a connector (4) that connects the main unit (2) inserted through the shaft (22) to the holder assembly (3), an operating unit (5) that is provided on the main unit (2) to allow the connector (4) to enter or leave the shaft (22) and a tension adjustor (6) capable of adjusting the tension of the connector (4).
