A scanning control system for use in a transmission or reception system of a facsimile equipment for controlling the secondary scanning speed of an image reader or recorder provided therein. In the transmission system, the scanning control system is coupled to an image memory for storing image information inputted from the image reader and supplying the image information to a coder, and responsive to the input signal and output signal of the image memory so as to detect the remaining capacity of the image memory. The scanning control system controls the secondary scanning speed in accordance with the detection results of the remaining capacity of the image memory. The secondary scanning speed is continuously increased under a condition of limiting it to a predetermined maximum speed when the remaining capacity is in a first range, maintained as it is when being in a second range, continuously decreased under a condition of limiting it to a predetermined intermediate speed when being in a third range, and the secondary scanning is stopped when being in a fourth range. In re-start after the stopping, the secondary scanning speed is set to a predetermined minimum speed.