A light-emitting apparatus includes: a radiation apparatus which includes a first laser diode and a second laser diode; a light guide which includes a first photoreceptor, a second photoreceptor, and a leak, and guides laser light received by the first photoreceptor and the second photoreceptor, the leak allowing leakage laser light to be leaked out in a direction crossing a light-guiding direction, the leakage laser light being part of the laser light; a converter which converts a wavelength of the leakage laser light leaked out of the light guide; and a detector which detects, at a non-radiation time in which laser light is not radiated, an electromotive force of the first laser diode, the electromotive force being based on laser light radiated by the second laser diode.