PROBLEM TO BE SOLVED: To provide an Eg5 inhibitor comprising a carbazole derivative or a carboline derivative as an active ingredient.SOLUTION: The polycyclic nitrogen-containing heterocyclic compound is represented by formula (I) (wherein Q1-Q4 are each nitrogen or -C(X)=) or its pharmaceutically acceptable salt.COPYRIGHT: (C)2012,JPO&INPIT【課題】カルバゾール誘導体、カルボリン誘導体等を有効成分として含有するEg5阻害剤の提供。【解決手段】式(I)で表される多環性含窒素複素環化合物又はその薬理学的に許容される塩。(式中、Q1~Q4は、窒素又は-C(X)=を表す)【選択図】なし