A communication speed control apparatus for controlling communication between a host device and an external device in accordance with a high-speed communication mode or a low-speed communication mode includes a list storage unit configured to store a list of specification information of external devices that are incompatible with the host device when data communication is carried out using the high-speed communication mode and a specification information obtainment unit configured to obtain external device specification information from the external device. A device determination unit is configured to determine if the external device specification information obtained from the external device corresponds to an incompatible external device based on the stored specification information and a communication speed control unit sets a data communication speed to the low-speed communication mode if the device determination unit determines that the external device in incompatible with the host device.