It is an object to provid a novel compound that has an excellent T-type calcium channel inhibitory activity and is specifically useful for prevention or treatment of pain, chronic kidney disease and atrial fibrillation. The present invention provides a novel triazinone compound of Formula (I):where each substituent in the formula is defined in detail in the description, and R1 means a hydrogen atom, or a C1-6 alkyl group, etc., E means a 7 to 14-membered non-aromatic fused heterocyclic group, L3 means a C1-6 alkylene group, etc., D means a C6-14 aryyl group or a 5 to 10-membered heteroaryl group each of which is optionally substituted, etc., a tautomer of the compound, or a pharmaceutically acceptable salt thereof, or a solvate thereof.
