We have been cultivation tests of Yacon (Polymnia sonchiforia) since 1987, and their results were reported. But it is not yet tested that the influence of ridging on the growth and yield of yacon.We tested on the influence of the methods of ridging on the growth and yield of yacon in Light-colored Andosol.Three experimental plots were made; level row plot, level row→high ridge (by earthing up) plot and high ridge plot. Three replications were made on each plot.The results were as follows:1) Growth of yacon of main stem in all stage was nonsignificant difference in each plot.2) The top was produced 748g/plant in level row plot, 900g/plant in level row→high ridge plot and 904g/plant in high ridge plot, but nonsignificant difference in each plot.3) The tuberous roots was produced 1268g/plant in level row plot, 1280g/plant in level row→high ridge plot and 1584g/plant in high ridge plot, but nonsignificant difference in each plot.4) From yield of yacon tuberous roots in each plot, it was suggestted that the earthing up at August 4, it would have little influence on yacon yield.5) From yield of yacon tuberous roots in each plot, it was judged that high ridge culture would be useful for the harvest of the tuberous roots of yacon with a potato digger.