An angiogenesis inhibitor effective in inhibiting angiogenesis which causes a disease is obtained by, for example, sterilely filtrating, disinfecting, and concentrating a product which is obtained as follows. That is, rice bran is extracted with hot water, the insoluble matter is filtrated, and the starch is decomposed by processing the filtrate with glucoamylase, thereby obtaining a water-soluble polysaccharide extract. Ammonium sulfate is added to a culture filtrate prepared by culturing Lentinula edodes of basidiomycetes, thereby obtaining an enzyme complex from the precipitate. This enzyme complex is added to the water-soluble polysaccharide extract, and the mixture is caused to react at a pH of 4.5 for 30 to 60 min and further react at a pH of 6.0 for 30 to 60 min, thereby biologically modifying the water-soluble polysaccharide extract and obtaining the product.藉由將水溶性多醣體萃取液與酵素複合體加在一起，使其在pH4.5下反應30~60分，再使其在pH6.0下反應30~60分，藉此對水溶性多醣體萃取液施加生物學上的修飾而獲得生成物質，再將該生成物質，例如進行除菌、滅菌並濃縮，做成血管新生抑制劑其可有效抑制造成疾病之原因的血管新生；前述水溶性多醣體萃取液是將米糠以熱水萃取、過濾不溶物，再將此濾液以葡萄糖澱粉酶處理並分解澱粉而獲得，前述酵素複合體是將硫酸銨添加至已培養擔子菌類香菇(Lentinula edodes)之培養濾液中，並自其沈澱物而獲得。
