To provide a multifrequency shared antenna which can obtain a desired characteristic as an intra-horizontal-plane directivity in a prescribed frequency by preventing the prescribed frequency from being driven by the antenna element of other frequencies and shares a feedline for feeding driving power to the antenna element of each different frequency.

This multifrequency shared antenna is provided with a first antenna element for emitting the radio wave of a frequency of f1, a second antenna element for emitting the radio wave whose frequency f2 (f2 > f1) is higher than that of the frequency of f1, and the feedline for feeding the driving power to the first antenna element and the second antenna element. The feedline has an end open line for grounding the feedline in a high frequency manner in the frequency of f2 between the first antenna element and the second antenna element.