An image capturing device includes a base formed with a first receiving space defined by a bottom wall and a first surrounding wall, and a second receiving space defined by a top side of the first surrounding wall and a second surrounding wall. A lens module is mounted on the base for generating an optical image of an object. An auto-focusing module is disposed in the second receiving space for auto-focusing the optical image based on an external voltage. A sensing module is mounted in the first receiving space and on the bottom wall of the base, is disposed under the auto-focusing module, and is spaced apart from the lens module at a predetermined distance for sensing the optical image focused by the auto-focusing module so as to generate an electrical output corresponding to the optical image.