An integrase inhibitor which comprises a compound represented by the formula (I):(I) wherein R<sp>C</sp> and R<sp>D</sp> in combination form a ring in cooperation with the adjacent carbon atoms, provided that the ring may be a fused ring; Y represents hydroxy, mercapto, or amino; Z represents oxygen, sulfur, or NH; and R<sp>A</sp> represents a group represented by the formula (II)(wherein ring C is a nitrogenous aromatic heterocycle), etc. The compound was found to have integrase inhibitory activity.
