Provided is a composite antenna adapted for reduction in size while ensuring sufficient electrical isolation between antenna elements. The composite antenna comprises ground plane, first feeding point connected to ground plane, first conductor connected to first feeding point and disposed linearly symmetrically with respect to axis, second conductor connected to first conductor and disposed linearly symmetrically with respect to axis, second feeding point disposed in a position along axis, third conductor connecting second feeding point and second conductor, and fourth conductor connecting second feeding point and second conductor and disposed in a linearly symmetrical manner to third conductor with respect to axis.