A communication module mounted on a communication apparatus includes a communication apparatus main body including a plurality of slots, and being insertable into or removable from the slots, a plurality of apparatus side signal processing circuits for processing a communication signal which is transmitted to or received from the communication module, and a switch LSI for changing a destination of the communication signal. The communication module includes a switching portion for performing dividing the communication signal transmitted or received at a communication speed of the communication module, and combining the communication signals transmitted or received at a communication speed of an external apparatus, a connector including a plurality of input-output ports, each of the plurality of the input-output ports being connected to the external apparatus respectively, and a plurality of connecting terminals being connected to the communication apparatus main body when the communication module is inserted into the slots.