The present invention provides a triazolopyridine compound having a prolyl hydroxylase inhibitory action and an erythropoietin production-inducing ability. The present invention relates to a compound represented by the following formula [I]:wherein each symbol is as defined in the specification, or a pharmaceutically acceptable salt thereof, or a solvate thereof, as well as a prolyl hydroxylase inhibitor or erythropoietin production-inducing agent containing the compound. The compound of the present invention shows a prolyl hydroxylase inhibitory action and an erythropoietin production-inducing ability and is useful as a prophylactic or therapeutic agent for various diseases and pathologies (disorders) caused by decreased production of erythropoietin.
