The present invention provides a line transition and a method for manufacturing the same. The line transition is constructed such that a planar circuit can be arranged in the direction parallel to the propagation direction of electromagnetic waves propagating through a solid waveguide, the coupling characteristics of the solid waveguide with the planar circuit formed on a dielectric substrate are not influenced by the assembly precision of the waveguide and the circuit, and the line transition characteristics are not affected by a variation in manufacturing the dielectric substrate. Notches are formed at the edges of the dielectric substrate in the vicinities of coupled-line pattern segments formed on a dielectric substrate. The notches are formed by punching through holes in a ceramic green sheet serving as a motherboard, firing the motherboard, and cutting the motherboard using dicing lines passing through the through holes.