A viewing angle switching method capable of conveniently adjusting region of interest (ROI) and user-friendly displaying image can be applied to a related camera. The viewing angle switching method includes setting at least one first region of interest and one second region of interest within a monitoring image, displaying the first region of interest on a monitoring screen, analyzing direction information of a switching command, and determining whether to rotate the second region of interest by a predetermined angle and to display the rotated second region of interest in accordance with the direction information.
