An imidazole derivative having antimicrobial activities against bacteria, fungi, yeast, pathogenic plant fungi and the like represented by the following general formula (I): ##STR1## wherein R.sub.1 means a hydrogen or halogen atom or a lower alkyl group, R.sub.2 denotes a hydrogen atom or an alkyl, alkenyl, haloalkyl or substituted or unsubstituted benzyl group, R.sub.3 stands for a hydrogen or halogen atom, and R.sub.4 is a substituted or unsubstituted benzylthio group, a phenylthio, alkylthio, alkenylthio, furfurylthio, alkoxy or phenoxy group or a halogen atom; or an acid addition salt thereof.