A communication apparatus includes a first antenna device connected to a first communication circuit and a first antenna ground, and a second antenna device connected to a second communication circuit and a second antenna ground. The direction in which the first antenna device resonates is away from the direction in which the second antenna device resonates. The first antenna device is provided with a first waveguide passive element which is radiation-coupled with the first antenna device. The second antenna device is provided with a second waveguide passive element which is radiation-coupled with the second antenna device. Because of the function of the first and second passive elements, radio interference between the first antenna device and the second antenna device installed in the communication apparatus can be reduced.