The present invention provides the compounds of the preventive medicine or medicine that can be used as disease extremely relevant to serum uric acid value etc.. That is, the present invention relates to it is represented by by formula (I), with xanthine oxidase inhibitory activity and can be used as the preventive medicine of disease extremely relevant to serum uric acid value or the Indoli zine derivatives or its pro-drug or its salt etc. of medicine. In formula, ring U indicates aryl or heteroaryl； R1 indicates halogen, hydroxyl etc.； R2 indicates halogen, hydroxyl, alkyl, alkoxy, fluorine-substituted alkyl, fluorine-substituted alkoxy etc.； M indicates 0 to 2； N indicates 0 to 3； R3 indicates hydrogen, fluorine etc..本發明提供了可用作與血清尿酸值異常相關的疾病等的預防藥或治療藥的化合物。也就是說，本發明涉及由式(I)所表示的、具有黃嘌呤氧化酶抑制活性並可用作與血清尿酸值異常相關的疾病的預防藥或治療藥的中氮茚衍生物、或其前體藥物或其鹽等。在式中，環U表示芳基或雜芳基；R1表示鹵素、羥基等；R2表示鹵素、羥基、烷基、烷氧基、氟取代的烷基、氟取代的烷氧基等；m表示0至2；n表示0至3；R3表示氫、氟等。
