Some ancient classical music instruments which those are still in use
 

Music no doubt is a very ancient thing of human history but is there any ancient music instrument still used in its original form?.

Welcome to MB, Dhwani!

I don't know about "classical music instruments", but for ancient instruments still used in their original form, the place to look might be among the Australian Aboriginies. They have the distinction of being the oldest surviving culture in human history, and they are still playing the bullroarer, the clap sticks, the digeridoo, and of course this well known instrument too:-