The purpose of this study was determine the effects of the benzalkonium iontophoresis on onychomycosis (hand). The participants consisted of 10 patients. This study was observed the change of normal nail length and infected nail square throe time : pre-treatment, after 6 treatment and after 10-treatment The results of this study were as follows. 1. The length increase of normal nail revealed significant statistically after 10 times treatment(p<0.05). 2. The square diminish of infected nail revealed significant statistically after 10 times treatment(p<0.05). 3. Infected nail thickening and spilt seeped and nail colon recovered after 10 times treatment. 4. The nail with iontophoresis recovered more quickly than the with nail lacquer in the same patients.