PURPOSE: To provide an antimycotic agent containing a specific imidazole derivative or its acid addition salt as active component, having extremely high antimycotic activity, exhibiting remarkable effect against animal-parasitic fungus and having high safety to man and animal.

CONSTITUTION: The objective antimycotic agent contains an imidazole derivative of formula (R is 6W9C straight or branched alkyl) or its acid addition salt as an active component. The compound of formula is e.g. 1-[1-(2-n- hexyloxyphenyl)vinyl]-1H-imidazole, etc. The compound of formula can be orally administered as a mixture with chemotherapeutically permissible diluent and carrier and, if necessary, with other excipient for forming a tablet, etc. It is also locally applicable in the form of ointment, etc.