Provided is a complex antenna which corresponds to both a circularly polarized wave and a linearly polarized wave. The complex antenna includes a substrate, a power feed terminal, four helical antenna devices disposed on the substrate at intervals of 90 degrees, four delay lines having different lengths by a quarter wavelength, and four switch modules which are connected to the power feed terminal in common and each of which is connected to each helical antenna device and each delay line. Each switch module selects one of a first mode in which the power feed terminal and each helical antenna device are directly connected and a second mode in which each delay line is connected to each helical antenna device so that a phase of a power feed fed from the power feed terminal and propagated from each delay line to each helical antenna device can be sequentially shifted by 90 degrees.