A numerical aperture (NA) controlling unit and a variable optical probe including the same are provided. The NA controlling unit includes: an aperture adjustment unit which controls an aperture through which light is transmitted; and a focus control unit that is disposed in a predetermined position with respect to the aperture adjustment unit, that focuses light transmitted through the aperture, and that has an adjustable focal length. The variable optical probe includes: a light transmission unit; a collimator that collimates light transmitted through the light transmission unit into parallel light; an NA controlling unit that focuses light on a sample to be inspected; and a scanner that varies a path of light transmitted through the light transmission unit such that a predetermined region of the sample is scanned by light that passes through the NA controlling unit.