An insertion-hole blockage-rate evaluation system is applied to a heat exchanger that includes a heat transfer tube and a tube support plate having an insertion hole formed therein for inserting the heat transfer tube therethrough. The tube support plate is displayed in a three dimensional manner in an elliptical diagram with a ratio between a long axis and a short axis being in a range from 1.0 to 2.0 inclusive, each of the tube support plates is serially arranged so as not to overlap on each other, and the insertion-hole blockage-rate evaluation system includes an imaging process of color-coding and displaying the diagram displayed in the three-dimensional elliptical shape according to a value of a blockage rate of the insertion hole acquired by checking the blockage rate of the insertion hole.