An augmented reality (AR) device including a variable focus lens of which a focal length may be changed by adjusting refractive power and adjusting the position of a focus adjustment region of the variable focus lens according to a direction of the user's view. The AR device may obtain an eye vector indicating a direction of the user's view using an eye tracker, adjust a refractive power of a first focus adjustment region of a first variable focus lens to change a focal length for displaying a virtual image, and complementarily adjust a refractive power of a second focus adjustment lens with respect to the adjusted refractive power of the first focus adjustment region.