A stimulus response material which is characterized by comprising stimulus response polymer, fiber, and water, the number average radius of fiber is 1~900 nm, and fiber is present dispersively. Besides, a medical material and an adhesion prevention material which uses a stimulus response material that comprises stimulus response polymer, fiber, and water, the number average radius of fiber is 1~900 nm, and fiber is present dispersively. To provide a stimulus response material of which application convenience is increased, and has both mechanical properties at the time of covering or required properties corresponding to various usages (such as biodegradability, organism adaptability, low toxicity, and etc.).一種刺激反應性材料,其特徵為包含刺激反應性高分子、纖維、以及水,纖維之數量平均直徑為1~900nm,且纖維係分散存在。又,一種醫療材料及沾黏防止材料,其使用包含刺激反應性高分子、纖維、以及水,纖維之數量平均直徑為1~900nm,且纖維係分散存在的刺激反應性材料。茲提供一種應用便利性得以提升,並兼備被覆時之力學特性或符合各種用途之要求特性(例如生物分解性、生物適應性、低毒性等)的刺激反應性材料。