Deterioration of reinforced concrete pipes is checked and the deterioration progress level is classified. Based on the inspection result, a portion to be inspected in detail in an inspection area is selected. With respect to the selected portion to be inspected in detail, the pipe thickness and the diameter of reinforcing bars are measured and the location of reinforcing bars in the portion to be inspected in detail are checked. Using the data of the thickness of a pipe, the diameter of the reinforcing bar and disposition of the reinforcing bars, structural analysis is carried out and the strength of the reinforced concrete pipe is calculated. The calculation result is used as information for evaluating the deterioration state of the reinforced concrete pipe.