Minoru Nishio graduated from Special Course of Japanese Literature Department of Tokyo University (1915).
Minoru Nishio taught successively at Matsumoto Women's Normal School, Seikei Girls' High School, Tokyo Municipal 2nd Middle School and Tokyo Women's University.
As part-time employee of Education Ministry inspected the situation of Japanese language teaching in Central and North China (1939). Became director of Kokuritsu Kokugo Kenkyiljo (National Japanese Language Research Institute) (since 1949) and professor of Literature Department of I-Iosei University (since 1946). Holds additional posts of trustee of Kokugo Gakukai (Japanese Language Society) and member of central committee of Nihon Bungaku Kyokai (Japanese Literature Association).