Method of forming pattern on group III nitride semiconductor substrate and method of manufacturing group III nitride semiconductor light emitting device

There is provided a method of forming a pattern on a group III nitride semiconductor substrate. A method of forming a pattern on a group III nitride semiconductor substrate according to an aspect of the invention may include: irradiating a laser beam onto at least one first region for preventing etching in a group III nitride semiconductor substrate; and etching at least one second region exclusive of the first region using the first region irradiated with the laser beam as a mask.