The invention discloses quinoxaline derivatives or salts thereof having PDE9-inhibiting activity and being useful as treating agent of dysuria and the like, which are represented by the formula (I)in the formula,R1 stands for C1-6 alkyl,R2 is absent,R3 stands for alkyl, aryl, saturated carbocyclic group, saturated heterocyclic group, acyl and the like,R4 stands for hydrogen, hydroxy, alkyl or amino,R5 and R8 each independently stands for hydrogen, halogen, alkyl, alkenyl, alkoxy, cyano or nitro,R6 and R7 each independently stands for hydrogen, halogen, alkyl, alkenyl, alkynyl, alkoxy, cyano, amino, carbocyclic group, heterocyclic group, COR9 or SO2R9,R9 stands for hydrogen, hydroxy, alkyl, amino, pyrrolidin-1-yl, piperidin-1-yl, pyperazin-1-yl or the like,X stands for S or O, and A1, A2 and A3 each independently stands for N or C.
