A wavelength converter includes a base having a first surface, a wavelength conversion part that has a second surface facing the first surface and converts first light that belongs to a second wavelength band into fluorescence that belongs to a second wavelength band different from the first wavelength band, junctions that join the wavelength conversion part and the base to each other, and an air layer located in a region that the first light enters and surrounded by the wavelength conversion part, the base, and the junctions. The first surface of the base has a first region curved in a direction, and the second surface of the wavelength conversion part has a second region facing the first region and curved in the same direction.