This article introduces three letters of Sata Ineko addressed to Narasaki Tsutomu. Narasaki Tsutomu (1901-1978)was an editor of the literary magazine Shincho in 1926-1945,and Sata Ineko(1904-1998) was a female writer known for her masterpiece KURENAI. Through the investigation of these letters, some of the new facts on Sata Ineko’s and Narasaki Tsutomu’s biographies were made clear.