The present invention provides a novel pyrimidine compound represented by Formula [I] and a salt thereof : [in the formula, the symbols are as defined in the specification], which is useful for treating, preventing and/or diagnosing seizure and the like in disease involving epileptic seizure or convulsive seizure (including multiple drug resistant seizure, refractory seizure, acute symptomatic seizure, febrile seizure and status epilepticus), as well as a medical use therefor.