A light source apparatus (100, 200) comprising: a light source configured to output light in a first wavelength region; and a wavelength conversion member (120, 220) including a first fluorescent substance (123, 223) and a second fluorescent substance (125, 225), the first fluorescent substance (123, 223) being excited by the light in the first wavelength region to emit light in a second wavelength region, the second fluorescent substance (125, 225) being stacked on the first fluorescent substance (123, 223) and excited by the light in the first wavelength region and the light in the second wavelength region to emit light in a third wavelength region, wherein the light in the first wavelength region which is output from the light source is light in a blue wavelength region, and the second fluorescent substance (125, 225) is a red fluorescent substance, characterized in that the first fluorescent substance (123, 223) is a yellow fluorescent substance, a rotatable base material (121, 221) provided with the first fluorescent substance (123, 223) and the second fluorescent substance (125, 225) includes a transparent member, the first fluorescent substance (123, 223) is stacked on a surface opposite to an incidence surface of the rotatable base material (121, 221) on which the light in the first wavelength region which is output from the light source is incident, the second fluorescent substance (125, 225) is stacked on the first fluorescent substance (123, 223), the first fluorescent substance (123, 223) and the second fluorescent substance (125, 225) are stacked on the rotatable base material (121, 221), and a reflection film (121a, 222a) is provided between the rotatable base material (121, 221) and the first fluorescent substance (123, 223), the reflection film (121a, 221a) reflecting the light in the second wavelength region. a light source configured to output light in a first wavelength region; and a wavelength conversion member (120, 220) including a first fluorescent substance (123, 223) and a second fluorescent substance (125, 225), the first fluorescent substance (123, 223) being excited by the light in the first wavelength region to emit light in a second wavelength region, the second fluorescent substance (125, 225) being stacked on the first fluorescent substance (123, 223) and excited by the light in the first wavelength region and the light in the second wavelength region to emit light in a third wavelength region, wherein the light in the first wavelength region which is output from the light source is light in a blue wavelength region, and the second fluorescent substance (125, 225) is a red fluorescent substance, characterized in that the first fluorescent substance (123, 223) is a yellow fluorescent substance, a rotatable base material (121, 221) provided with the first fluorescent substance (123, 223) and the second fluorescent substance (125, 225) includes a transparent member, the first fluorescent substance (123, 223) is stacked on a surface opposite to an incidence surface of the rotatable base material (121, 221) on which the light in the first wavelength region which is output from the light source is incident, the second fluorescent substance (125, 225) is stacked on the first fluorescent substance (123, 223), the first fluorescent substance (123, 223) and the second fluorescent substance (125, 225) are stacked on the rotatable base material (121, 221), and a reflection film (121a, 222a) is provided between the rotatable base material (121, 221) and the first fluorescent substance (123, 223), the reflection film (121a, 221a) reflecting the light in the second wavelength region.