An antenna unit and a communication apparatus are provided, which are operable with respect to wireless systems having three, or more frequencies by employing 2 sets of antenna elements, and which can realize such an antenna structure having a high freedom degree, while the antenna structure can be applied to frequency arrangements as to the plurality of wireless systems. An antenna unit includes a first antenna element 11 connected to a first wireless system operated in a first frequency band, to which electric power is fed; and a second antenna element 12 connected to a second wireless system operated in a second frequency band and a third frequency band, to which electric power is fed; in which the first antenna element 11 and the second antenna element 12 are arranged in a predetermined interval in a substantially parallel manner; and a cut off section 16 for electrically cutting off a connection between the first antenna element 11 and the first wireless system is provided at a power feeding portion “P1 ” of the first antenna element 11.