The surgical instrument includes a long member, a link portion, a treatment portion, a drive control unit, and a power transmission member. The link portion includes a first rotary shaft having a first rotation axis perpendicular to the longitudinal axis at a distal end of the long member and a second rotary shaft that is movable with respect to the first rotation axis using the first rotation axis as a center of rotational movement, that has a second rotation axis that extends in parallel with the first rotation axis, and that is linked to the shaft. The power transmission member is fixed to a part of an outer circumference of the shaft such that the first path and the second path face opposite directions in a circumferential direction of the shaft, and when viewed in a direction in which the first rotation axis and the second rotation axis extend, the first path and the second path intersect at a point between the first rotation axis and the second rotation axis.
