Improvement of the luminous efficiency of a fluorescent layer is achieved. A wavelength conversion element is provided that converts incident, light from a wavelength range thereof to another wavelength range, the wavelength conversion element including a fluorescent layer including first particles and second particles dispersed in a first binder, the second particles being smaller than the first particles, wherein the first particles fluoresce under light having the wavelength of the incident light, and the first binder accounts for from 10% inclusive to 50% exclusive by volume of a particle group including the first particles and the second particles in the fluorescent layer.