An antenna includes two elements having an antenna element which resonates by a frequency f1 and a ground wire element which resonates by a frequency f2 higher than the frequency f1. The antenna element is directed so that an antenna radiation part is located to be substantially parallel to a surface of a casing on which an operating part is provided. The ground wire element is directed so that a ground wire radiation part is located substantially vertically to the surface of the casing on which the operating part is provided. Further, a space between a feeding terminal connecting part of the antenna element and a ground terminal connecting part of the ground wire element is set to be equal to a space between a feeding terminal and a ground terminal and the feeding terminal connecting part is arranged to be parallel to the ground terminal connecting part.