A high-frequency coupler includes a ground, a coupling electrode which faces the ground and is supported so as to be separated by a negligible height with respect to a high-frequency signal, a resonating unit for increasing a current flowing into the coupling electrode, a supporting unit which is connected to the resonating unit, and a short-circuiting unit which short-circuits the tip portions of the coupling electrode, in which an infinitesimal dipole constituted by a line connecting the center of the charges accumulated in the coupling electrode and the center of mirror-image charges accumulated in the ground is formed, and the high-frequency signal is transmitted toward a high-frequency coupler of a communication partner so that the angle θ formed in the direction of the infinitesimal dipole is substantially 0 degrees.