<p>Provided is a method whereby a triazole derivative having a (1,3-dioxan-5-yl)thio group of improved qualities can be produced at an elevated yield by using an industrially more advantageous operation while reducing impact on the environment. Also provided is a triazole derivative having a high purity. Sodium hydroxide or sodium ethoxide is used in a reaction between an epoxide and a thioester. Hydrochloride of a diol compound is reacted with an aldehyde in the presence of trimethylsilyl chloride together with an organic base and in the presence or absence of an alcohol. Further, sodium methoxide is used in a coupling reaction between a phosphonic acid ester and an aldehyde.</p>
