There is provided a novel triazinone compound that has an excellent T-type voltage-dependent calcium channel inhibitory activity and is specifically useful for treatment of pain. A compound of Formula (I), a tautomer of the compound, a pharmaceutically acceptable salt thereof, or a solvate thereof: where each substituent is defined in detail in the description or claims, for example R1 is H or C1-6 alkoxy, etc., each of L1 and L2 is independently a single bond or NR2, etc., L3 is C1-6 alkylene, etc., A is C6-14 aryl or 5 to 10-membered heteroaryl which is optionally substituted, etc., B is C3-11 cycloalkylene, etc., D is C6-14 aryl or 5 to 10-membered heteroaryl which is optionally substituted, etc.