A material using an aglycone type isoflavone which has the effect of improving the endometriosis is provided. Also, a method of producing an endometriosis improving material includes: inoculating legumes with aspergillus oryzae and koji treating them, and hydrolyzing the proteins in the products by hydrolyzing the products of the koji treatment and decomposing glycosides of the isoflavone compounds in the legumes, then producing isoflavone compounds containing a large amount of aglycone, and producing a material for improving endometriosis containing aglycone type isoflavone from the legumes.
