A wavelength converting device includes a heat dissipating member, a wavelength converting member, and a connecting member. The wavelength converting member is disposed on the heat dissipating member and contains a fluorescent material and a holding body including aluminum oxide, magnesium oxide, zirconium oxide, lutetium oxide, titanium oxide, chromium oxide, tungsten oxide, divanadium pentoxide, molybdenum trioxide, sodium oxide, yttrium oxide, silicon dioxide, boron oxide, or diphosphorus pentoxide. The connecting member contains a metal material and connecting the heat dissipating member and the wavelength converting member. The wavelength converting member includes an upper surface, side surfaces, and a lower surface. The connecting member is thermally connected to the side surfaces and the lower surface of the wavelength converting member.