The object is to enable the calculation of load transfer paths in case of distributed load applied to the structure with the numerical structure-analysis calculation system. The value of the parameter U** at each point is calculated according to the ratio of the complementary strain energy U at the application of load without fixing the point in the structure and the complementary strain energy U′ at the application of load with fixing one point in the structure. In the actual calculation, according to the complementary strain energy U, and the flexibility matrix CAC with respect to the loading point A and one point C in the structure, and the inverse matrix CCC−1 of the flexibility matrix with respect to point C, and the load pA at the loading point A, the value of the parameter U** (CACCCC−1CCApA·pA/(2U)) at point C is calculated. Or, from the complementary strain energy U, and the inverse matrix CCC−1, and the displacement dC at point C, the value of the parameter U**(dC·CCC−1dC/(2U)) at point C is calculated.