To provide a high-frequency module having an antenna configured by integrally connecting a slot plate laid out with radiation slots to a plate having plural thin plates formed with a waveguide for supplying power to the slot plate, using a diffusion bonding. The waveguide of the antenna is connected to a dielectric waveguide of a high-frequency package via a waveguide provided on a resin substrate, thereby configuring a slot antenna at low cost, and connecting a power-supply slot of the slot antenna to a waveguide terminal of the high-frequency package with low loss.
