There is provided a communication device that includes a first circuit board which includes a first ground pattern (GND) and a first signal line formed on a substrate, a ground pin electrically coupled with the first GND, where the ground pin protrudes from an end of the substrate, and a signal pin formed in the substrate and electrically coupled with the first signal line, where the signal pin protrudes from the end. The communication device further includes a send circuit board which includes a second GND and a second signal line, wherein when an end of the circuit board is inserted into a space between the ground pin and the signal pin, the first signal line and the second signal line are electrically coupled with each other via the signal pin and the first GND and the second GND are electrically coupled with each other via the ground pin.