The present invention relates to a dispersion-type feed additive composition for ruminants containing 40% by weight or more and less than 65% by weight of a basic amino acid which is a biologically active substance and a method of producing the same, and provides granules which have rumen bypass properties, can release the biologically active substance at a high concentration in the small intestine of a ruminant animal to thereby promote the milk production of a lactating cow, and can be shaped into an arbitrary form being hardly classified when added to a feed and a method of continuously producing the above-described granules with a high efficiency. The invention relates to a feed additive composition for ruminants which contains at least one protective agent selected from a hydrogenated vegetable oil and a hydrogenated animal oil having a melting point higher than 50°C and lower than 90°C, 0.05 to 6% by weight of lecithin, water, and 40% by weight or more and less than 65% by weight of a basic amino acid, and a method of producing the feed additive composition for ruminants, the method including solidifying a molten mixture, which includes at least one protective agent selected from a hydrogenated vegetable oil and a hydrogenated animal oil having a melting point higher than 50°C and lower than 90°C, lecithin, and a basic amino acid, by immersing the same in water.