A high-frequency package comprises a dielectric substrate, on an upper face of which a mounting portion of a high-frequency circuit component is formed, a first line conductor formed on the upper face for transmitting high-frequency signals, a first coplanar grounding conductor, a second line conductor formed on a lower face, a second coplanar grounding conductor, a through conductor formed inside for connecting the first and second line conductors, a grounding through conductor connecting the first and second coplanar grounding conductors, a metal terminal bonded to the second line conductor, and grounding metal terminals bonded to the second coplanar grounding conductor, wherein a gap between the grounding metal terminals is equal to or less than of a wavelength of high-frequency signals.