The present invention provides a method for manufacturing a group III nitride semiconductor light emitting element, with which warping can be suppressed upon the formation of respective layers on the substrate, a semiconductor layer including a light emitting layer of excellent crystallinity can be formed, and excellent light emission characteristics can be obtained; such a group III nitride semiconductor light emitting element; and a lamp. Specifically disclosed is a method for manufacturing a group III nitride semiconductor light emitting element, in which an intermediate layer, an underlayer, an n-type contact layer, an n-type cladding layer, a light emitting layer, a p-type cladding layer, and a p-type contact layer are laminated in sequence on a principal plane of a substrate, wherein a substrate having a diameter of 4 inches (100 mm) or larger, with having an amount of warping H within a range from 0.1 to 30 μm and at least a part of the edge of the substrate warping toward the principal plane at room temperature, is prepared as the substrate; the X-ray rocking curve full width at half maximum (FWHM) of the (0002) plane is 100 arcsec or less and the X-ray rocking curve FWHM of the (10-10) plane is 300 arcsec or less, in a state where the intermediate layer has been formed on the substrate and where thereafter the underlayer and the n-type contact layer are formed on the intermediate layer; and furthermore the n-type cladding layer, the light emitting layer, the p-type cladding layer, and the p-type contact layer are formed on the n-type contact layer.