The invention relates to microwave technology and can be used in measuring technology and wireless communication. The technical result is a waveguide-to-microstrip transition which provides reduced signal transmission losses and increased working bandwidth together with a low wave reflection coefficient. A contacting metal layer is arranged on an upper surface of a dielectric circuit board around a micro-strip probe, without electrical contact with the micro-strip probe and a micro-strip transmission line and forming an internal area on the dielectric circuit boar being a waveguide channel area. A closed waveguide section having a slot in the area of the microstrip transmission line is arranged on the contacting metal layer. At least one metallized transition through-hole is formed along a perimeter around the area of the waveguide channel in the metal layers and in the dielectric circuit board, and at least one non-metallized through-hole is formed inside the waveguide channel area.