A method for producing a light reflecting layer-including optical semiconductor element includes the steps of temporarily fixing electrode surfaces of a plurality of optical semiconductor elements each having the electrode surface provided with an electrode, a light emitting surface opposing the electrode surface and provided with a light emitting layer, and a connecting surface connecting a peripheral end edge of the electrode surface to that of the light emitting surface to a temporarily fixing sheet at spaced intervals to each other; filling a first gap between the optical semiconductor elements that are next to each other with a light reflecting sheet and forming a light reflecting layer on the connecting surfaces of the plurality of optical semiconductor elements; removing the light reflecting layer attaching to the light emitting surfaces of the plurality of optical semiconductor elements; and cutting the light reflecting layer between the optical semiconductor elements that are next to each other.