An augmented reality (AR) device for obtaining depth information of an object in a real world, includes: a gaze tracking sensor configured to obtain a gaze point by tracking a gaze direction of a user's eye; a depth sensor configured to obtain depth information of the object; a memory storing one or more instructions; and at least one processor configured to execute the one or more instructions to: determine a region of interest (ROI) confidence level indicating a degree to which at least one partial region within a field of view (FOV) of the AR device is predicted as an ROI, based on at least one of a moving speed, an acceleration, a fixation time, a fixation number, or a location of the gaze point; determine an ROI based on the ROI confidence level; and set a parameter for controlling an operation of the depth sensor to obtain depth information of the object within the ROI.