A Group III nitride semiconductor light emitting device having a light emitting layer (6) bonded to a crystal layer composed of an n-type or p-type Group III nitride semiconductor, the Group III nitride semiconductor light emitting device being characterized by comprising an n-type Group III nitride semiconductor layer (4) having germanium (Ge) added thereto and having a resistivity of 1.times.10.sup.-1 to 1.times.10.sup.-3 .OMEGA.cm. The invention provides a Ge-doped n-type Group III nitride semiconductor layer with low resistance and excellent flatness, in order to obtain a Group III nitride semiconductor light emitting device exhibiting low forward voltage and excellent light emitting efficiency.