Provided is a compound represented by formula (I) that has an antiviral effect. In formula (I): A1 represents CR1AR1B, S or O； A2 represents CR2AR2B, S or O； A3 represents CR3AR3B, S or O； A4 represents CR4AR4B, S or O [wherein the ring-constituting atoms consisting of A1, A2, A3, A4, a nitrogen atom adjacent to A1 and a carbon atom adjacent to A4 include one or two hetero atoms； R1A and R1B independently represent hydrogen, halogen, alkyl, etc.； R2A and R2B independently represent hydrogen, halogen, alkyl, etc.； R3A and R3B independently represent hydrogen, halogen, alkyl, etc.； R4A and R4B independently represent hydrogen, halogen, alkyl, etc.； R3A and R3B may together form a non-aromatic carbon ring or a non-aromatic heteroring； X represents CH2, S or O； R1's independently represent halogen, hydroxy, etc.； m is an integer of 0-2； and n is an integer of 1-2].
