Wavelength conversion element, light source apparatus, and image projection apparatus

A manufacturing method of a wavelength conversion element that includes a fluorescent portion in which fluorescent particles are dispersed in a binder, wherein the fluorescent portion has a first surface and a second surface which are opposite to each other in a thickness direction and excitation light is irradiated from a second surface side, the manufacturing method comprising the steps of:

• preparing a first material in which the fluorescent particles are dispersed with a first volume density in the binder and a second material in which the fluorescent particles are dispersed with a second volume density higher than the first volume density in the binder;
• and
• laminating the first material and the second material so that the second material is located on a first surface side and a thickness of the fluorescent portion is at least 5 times as long as an average particle size of the fluorescent particles.