A surgical system includes a manipulator configured to move the distal end portion in a three-dimensional space with respect to the proximal end portion, an instrument holder configured to hold a surgical instrument that is continuous with the distal end portion of the manipulator and includes a long-axis shaft and a treatment tool provided on the distal end portion of the shaft in a posture in which the shaft extends in a reference direction D, and a swing mechanism interposed between the manipulator and the treatment tool and configured to swing the distal end portion of the shaft in the radial direction centered on the axis of the shaft extending in the reference direction.
