An image sensor module includes a substrate, an image sensor, and a connecting plate. The substrate includes a supporting portion and an extending portion extending from one side of the supporting portion. The supporting portion includes an upper surface and a lower surface opposite to the upper surface. The supporting portion defines a through hole penetrating the upper surface and the lower surface and a receiving recess communicating the through hole on the lower surface. The thickness of the extending portion is less than the thickness of the supporting portion. The image sensor is received in the receiving recess and is electrically connected to the substrate. The connecting plate is electrically connected to the extending portion, the thickness of the connecting plate is less than or equal to the thickness difference between the extending portion and the supporting portion.