A structure monitor system comprising a measuring unit 3 for measuring distortions of the structure S at respective points on a boundary by using an optical fiber sensor 2 laid on the boundary of the structure, numerical analysis unit 5 for calculating a distortion at a specified point on the structure S by a numerical analysis method with distortions measured by the measuring unit as a boundary condition, and a display unit 6 for displaying information on an analysis distortion by the numerical analysis unit 5 in a association with a position on the structure S.