An image capturing device includes a lens unit, an image sensor, a face recognition unit, a selecting unit, an auto-focusing (AF) unit and a driving unit. The lens unit focuses images onto the image sensor. The image sensor converts the images into electronic signals. The face recognition unit locates any faces in a current image. If faces are detected, the selecting unit indicates to a user where the faces are located in the image, and selects one of the locations as a main focus area in response to a user input. The driving unit is configured for moving the lens unit. The AF unit controls the driving unit to focus the lens unit according to the selected location.