The present invention provides a light emitting device comprising: an excitation light source which radiates excitation light; a wavelength converting member which absorbs and converts the wavelength of at least part of the excitation light radiated from the excitation light source, and releases light with a predetermined wavelength band; a light guide for guiding the excitation light radiated from the excitation light source to the wavelength converting member, with one end at the excitation light source and the other end at the wavelength converting member, wherein the refractive index of the cross-sectional center region (core) is higher than that of the circumferential region (clad); and a thermally conductive transparent film which contacts with the wavelength converting member.