Abstract: A target support tool includes: a base member including a first arm and a second arm connectable to each other to form a bent therebetween; a magnetic support part at least on the first arm; and a retroreflector at the bent of the base member.

Abstract: A tilt analysis system including: a surveying device configured to survey a position of a survey target device by irradiating the survey target device with surveying light, the survey target device including an attachment portion to be attached to a columnar object, and a reflector that reflects the surveying light; a portable terminal device; a reference value acquisition unit configured to acquire a first point obtained by surveying the position of the survey target device attached to a bottom of the columnar object; a column top value acquisition unit configured to acquire a second point obtained by surveying the position of the survey target device attached to the top of the columnar object; a tilt analysis unit configured to generate tilt information indicating in which direction the columnar object tilts; and a tilt information output unit configured to output the tilt information generated by the tilt analysis unit.