A high-frequency circuit includes a dielectric substrate, a stripline formed on a surface of the dielectric substrate, a ground conductor provided on a back surface of the dielectric substrate, in which a pattern cut-out portion through which a part of the back surface of the dielectric substrate is exposed is formed, and a stub having a first end connected to an edge portion of the ground conductor defining the pattern cut-out portion and a second end arranged at a distance from the edge portion.