We report a novel structure of a selectively grown buried-ridge (SGBR) type nitride-based laser diode structure grown on sapphire and lateral epitaxial overgrowth (LEO) substrates by metal-organic chemical vapor deposition (MOCVD). The AlGaN layers were designed for current confinement into ridge as well as to enhance lateral optical confinement by introducing an index difference between MQW and AlGaN layers in the lateral direction. The I-V characteristics of SGBR structure on LEO substrate showed no leakage current upto a reverse bias of -10V. From an EL image through transparent metal, we demonstrated that the current path was well defined into the ridge region.