Abstract: A case of Trichomycosis Axillaris has been studied by SEM.It showed that surrounding the affected axillary hairs there were many nodular or tubular concretions in various size and irregular shape.Some of them were confluent,or enclosed the affected hairs.There were a lot of holes,pits and prominces on teh surfaces of the concretins.On the surfaces of the concretions or in their pits there were lots of Corynebacterium Tenuis.