A heparanase activity inhibitor comprising, as an active ingredient, a cyclic carboxamide derivative represented by formula (I): wherein n is an integer of 1 to 3, R 1 is hydrogen or a C1-6 hydrocarbon group optionally substituted with hydroxyl, X is -CH 2 - or a group represented by -N(R 2 )-, and R 2 is hydrogen or a C1-6 hydrocarbon group optionally substituted with hydroxyl, or a salt thereof.本發明係關於一種包含下述通式(I)所示之環狀甲醯胺衍生物或其鹽作為活性成分而成之乙醯肝素酶活性抑制劑:(通式(I)中,n為1~3之整數,R1為氫原子或可由羥基取代之碳數1~6之烴基,X為-CH2-或-N(R2)-所示之基,R2為氫原子或可由羥基取代之碳數1~6之烴基)。