PURPOSE: To provide a light-emitting element which can emit light at two wavelengths by one element by a method wherein lower-part light which causes a noise or the like in conventional cases is utilized.

CONSTITUTION: A dual-wavelength light-emitting element H is provided with a light-reflecting layer between a p-n junction part X and an upper-part electrode 7. Thereby, when two lightemitting operations at different wavelengths are required, it is sufficient to use one element as compared with conventional cases in which two elements are used. As a result, the structure of a device such as a sensor or the like and its manufacture can be simplified, and its manufacturing cost can be reduced. In addition, when semiconductor materials constituting the light-emitting element are combined, they can be combined in a wider range as compared with conventional cases in which they are limited to materials not generating lower-part light.