The invention relates to a high-frequency circuit board that can efficiently radiate heat generated in a mounted electronic component without reducing the degree of freedom in design, a high-frequency circuit module including the high-frequency circuit board, and a radar apparatus including the high-frequency circuit module. A dielectric substrate (3) includes a mounting portion (4) that is disposed on one surface (3a) of the dielectric substrate (3) and on which an electronic component (2) is to be mounted, and a waveguide (5) that is formed in the dielectric substrate (3). The mounting portion (4) and the waveguide (5) are connected with each other through a heat conductor (6) having a thermal conductivity higher than that of the dielectric substrate (3).