If you really like him as a teacher and are sure you aren't interested in him in any other way, you could try making that clear and see if he responds well. You could just do the usual--be busy if he asks you out, etc. If he doesn't get the message, then you'll need to be direct. You might be able to keep working with him on a more professional basis.

In fact, I would say that if you are interested in him romantically, that's the time to get another teacher. You don't want the unequal power dynamics of the teacher-student relationship getting mixed up with romance.

If a little coolness on your part doesn't solve the problem, then you could present him with a choice: tell him you don't want to mix dancing and dating, so if he wants to date you, you'll switch to a different teacher. That would certainly test his interest in you, if he's willing to give up the income to see you socially. My guess is he won't, but it will be his choice, not your rejection, so it would be easier to continue working together.