A device and method for providing an augmented reality (AR) image are provided. The device includes a display configured to alternately display a first image including an object at an object position and a second image including a mask for blocking transmission of light incident on the display at the object position; a processor configured to determine a time period and control the display to alternately display the first image and the second image during the time period; and a polarization switch configured alternately polarize the light incident on the display at a switching period determined based on the time period.