The surgical tool comprises: a treatment section for treating an object to be treated a first traction member and a second traction member connected to the treatment section a power source for generating the power to operate the treatment section a switching section for switching the transmission of power from the power source to the first traction member and the second traction member between a state in which power can be transmitted and a state in which power cannot be transmitted and a tension-applying section for applying a specified initial tension on the first traction member and the second traction member.
