An object of the present invention is to further miniaturize a module substrate with an antenna while maintaining desirable characteristics. A module substrate with an antenna according to the invention has a substrate body and first and second radiation conductors and provided on one surface of the substrate body and being symmetrical. The first and the second radiation conductors asymmetrical with respect to a first line B that passes a power-supplying the first radiation conductor and a power-supplying point of the second radiation conductor. Therefore, the wavelength of radio waves radiated from the current flowing in one direction as viewed from the first line B is different from that of radio waves radiated from the current flowing in the other direction as viewed from the first line B. As a result, the substrate body can be miniaturized while securing a broader band than the conventional module substrates.