Buckwheat is considered to be one of the useful sources of rutin in food. To analyze the varietal differences and heritability for the rutin content in seed and leaf in common buckwheat, twenty seven cultivars and strains introduced from the major countries where buckwheat is cultivated were tested. Plant materials were grown in 1992 and 1993 in a randomized block design with two replications each year in the Experimental Field of Shinshu University. Rutin content in seed and leaf was determined by high performance liquid chromatography, and the main characters were also observed. The mean values of the rutin content showed a wide range of variation. The seed rutin content of the tetraploid cultivars of Japan was higher than that of the diploid ones. However, there was no significant difference between the ploidy level for leaf.