The present invention provides a compound having antiviral activity, especially having arenavirus proliferation inhibitory activity, and / or a medicament comprising the compound. More preferably, the present invention provides a compound having proliferation inhibitory activity on the Old World arenaviruses such as Luna virus, Lassa virus, and lymphocytic choriomeningitis virus and / or the New World arenaviruses such as Junin virus, and / or a medicament comprising the compound.An arenavirus proliferation inhibitor comprising a compound represented by Formula (I) or a prodrug thereof or a pharmaceutically acceptable salt thereof:(wherein R1 is carboxy, or the like; A3 is CR2 or N; R2 is a hydrogen atom, halogen, hydroxy, or the like; R3 is a hydrogen atom, hydroxy, carboxy, cyano, formyl, alkyl optionally substituted with Substituent group F, or the like; either A1 or A2 is CR6R6, and the other is NR7, or A1 is CR8R9, and A2 is CR10R11; and R5, R6, R7, R8, R9, R10, and R11 are each independently a hydrogen atom, carboxy, cyano, alkyl optionally substituted with Substituent group F, or the like).