PURPOSE: To inexpensively obtain a large amount of rutin industrially and advantageously by culturing callus derived from an organ and/or tissue of a plant containing rutin.

CONSTITUTION: Bud of Sophora japonica L. is sterilized with ethyl alcohol and cut to give a small piece. Then the small piece is inoculated into a medium comprising a carbon source such as sucrose, an inorganic component such as Ca, an organic component such as biotin and indole-3-acetic acid, etc., irradiated with light rays at 18-32°C at 190-500nm wavelength at 100-10,000lux intensity for several days to several weeks and sterilely subjected to callus induction culture to give callus. Then the callus is inoculated into a liquid medium having reduced nutrients of the above-mentioned induction medium, irradiated in the same way with 20-300l/minute based on 1m3 medium aeration and subjected to rutin biosynthesis cell culture for plural days to several weeks to give a culture mixture. Then the culture mixture is filtered, cells are dried, ground, impregnated with water and extracted to produce rutin.