An image detecting module includes a socket, a circuit board, an image sensor, an elastic element, a filter and a holder. The socket comprises an inner circumference wall along a main axis for defining an inner space and a platform that extended from the inner circumference wall. Pluralities of mounting holes are provided on the holder and pluralities of protrusions are provided on the socket; thus the elastic element and the filter could be fixed between the platform and the holder by fitting the protrusions into the mounting holes.