Genshun KOISHI (1743-February 9, 1809) was a Rangakusha (a person who studied Western sciences by means of the Dutch language) and Ranpoi (a person who studied Western medicine by means of the Dutch language) in the late Edo period.
小石元俊（こいしげんしゅん、寛保3年（1743年）-文化(元号)5年12月25日(旧暦)（1809年2月9日）は、江戸時代後期の蘭学者、蘭方医。