A conductive-transmission-line waveguide converter comprising a waveguide for transmitting an electromagnetic wave, a wiring board brought into contact with a side of the waveguide opposite to a side of the waveguide for inputting an electromagnetic wave, being oriented perpendicularly to a longitudinal axis of the waveguide, a first probe provided in an area on the wiring board inside the waveguide for taking in a first linearly polarized wave, and a second probe provided in an area on the wiring board inside the waveguide for taking in a second linearly polarized wave perpendicular to the first linearly polarized wave, wherein the first probe and the second probe are respectively created along mutually perpendicular first and second axis lines, which both pass through a cross point of the wiring board and the longitudinal axis of the waveguide, and a first center line passing through the middle of each transversal line segment of the first probe is shifted from the first axis line and a second center line passing through the middle of each transversal line segment of the second probe is shifted from the second axis line in such a way that, on the wiring board, the first probe is farther separated away from the second probe.