As for the stress analysis of a manhole cover, the numerical analysis is most, and the analysis along a real machine is not done. Therefore, it is likely to differ from the actual one. The experiment analysis was done to a three-dimensional analysis in this research a powerful stress frozen method. As a result, it has been understood that stress concentrate on the fillet surface of the edge volume most. It has been understood that careful further correspondence is necessary in shape and the size of the edge volume fillet surface in the safety design.