Abstract: In a device for evaluating torsional structural performance of girder according to an embodiment of the present disclosure, a guide unit of a support member formed in a shape of an arc having its center that matches a shear center of the girder rotatably supports a rotating member, so that the shear center of the girder matches a center of torsion during clockwise or counterclockwise rotation of the rotating member, thereby measuring an accurate angle of twist and preventing an incident in which the rotating member escapes due to separation of a component by a rotational force.