A light source unit according to an embodiment of the present disclosure includes: a light source section; and a wavelength conversion element that is excited by exciting light from the light source section to emit fluorescent light. The wavelength conversion element includes a substrate that is rotatable around a rotation axis, a phosphor layer including a plurality of phosphor particles, and a quantum-dot layer including a plurality of quantum dots. The phosphor layer and the quantum-dot layer are disposed in this order relative to the light source section.