Many studies have been conducted about the use of 名 (na; name) and 名誉 (meiyo; honor) in explaining the temperament of samurai. It is evident that many researchers consider na and meiyo to be respected by samurai, and this temperament of samurai is always as an important theme when we make a study about samurai. To know the temperament of samurai in the Middle Ages, Gunki Monogatari which has much description about samurai and wars will be useful. And, the most well known Gunki Monogatari is Heike Monogatari which about the Genpe War. In Heike Monogatari, such as with na koso oshikere and kodai ni na wo agetari. there is clearly extensive use of na with reference to samurai, especially in the area of combat. In the present study, I investigate the use of na as an important influential element in the action of samurai. I also examine the meaning of na in Heike Monogatari.