Present invention provides a compound of formula (I) [Formula 1] provides a pharmaceutical composition containing a compound of formula (I) as well as the compounds represented by the formula, is used as a PARP inhibitor thereof, wherein, n, s, R 1, R 2 , Y R 3, Q, and X have the meanings defined.本発明は式(I)【化1】で表される化合物、それらをPARP阻害剤として用いることばかりでなく前記式(I)で表される化合物を含有させた薬剤組成物を提供し、ここで、n、s、R1、R2、R3、Q、XおよびYは定義する意味を有する。