Problem to be solved: to provide a compound which is excellent in fungicidal activity, excellent in safety and can be advantageously synthesized in an industrial manner, and fungicide for agricultural horticulture containing this as an active ingredient.Solution: 1,3,5,6-tetrasubstituted thieno [2,3-d] pyrimidine-2,4 (1H, 3H) Dione compound or salt thereof represented by formula (I).No selection【課題】殺菌活性に優れ、安全性に優れ、且つ工業的に有利に合成できる化合物並びにこれを有効成分として含有する農園芸用殺菌剤を提供する。【解決手段】式（Ｉ）で表される１，３，５，６－テトラ置換チエノ［２，３－ｄ］ピリミジン－２，４（１Ｈ，３Ｈ）ジオン化合物又はその塩。【選択図】なし
