PURPOSE: To compensate the deterioration of cross polarization characteristics due to the shift in relative phase, by providing a phase variable and rotating type phase shifter in an antenna device in common use of a polarized wave and compensating the relative phase shift amount on an arbitrary plane at the end of the frequency band in use.

CONSTITUTION: A phase variable rotating type phase shifter 11 consists of a main waveguide 7, an external cavity train, a phase adjusting bis 9, and the amount of phase of each cavity is determined by adjusting the resonance frequency of a cavity 10 with the bis 9. To compensate the relative phase shift at the low frequency end of the frequency band in use, the leading phase due to the inductive cavity 10 is utilized, and to compensate that at the high frequency end, the capacitive phase of the cavity 10 is utilized. An orthogonal polarized wave common antenna feeder consists of a 180° phase fixed rotating type phase shifter 13, 90° phase fixed rotating type phase shifters 12 and 11, and the relative phase shift at the point A of an input signal passing through a transmission antenna 6 and a reception antenna 5 can be outputted to a polarized wave branching filter 4 as a signal having excellent cross polarization characteristics by setting the phase shifters 13∼11.