High-frequency circuit components are disclosed in which parasitic capacitance between a high-frequency circuit element and a substrate is reduced and mechanical strength is improved. An exemplary component has a conductive substrate, a coil as the high-frequency circuit-element, a mounting board including a thin dielectric film on which the coil is mounted, and a support board that couples the mounting board to the substrate. The mounting board is coupled so that it floats relative to the substrate as a result of deliberate warping of the support board.