A nitride semiconductor light emitting element is provided with: a substrate; a buffer layer that is provided on the substrate; a base layer that is provided on the buffer layer; an n-side nitride semiconductor layer that is provided on the base layer; an MQW light emitting layer that is provided on the n-side nitride semiconductor layer; and a p-side nitride semiconductor layer that is provided on the MQW light emitting layer. An x-ray rocking curve half-value width ω (004) with respect to a (004) plane, i.e., the crystal plane of the nitride semiconductor, is 40 arcsec or less, or the x-ray rocking curve half-value width ω (102) with respect to a (102) plane is 130 arcsec or less, and the rate P (80)/P (25) between light output P (25) at 25° C. and light output P (80) at 80° C. with a same operating current is 95% or more.