Provided is a white resin composition that can maintain a high degree of whiteness even after undergoing a thermal resistance test. A white resin composition contains: a white pigment; a surface-treated calcium carbonate in which particle surfaces of a synthetic calcium carbonate with an average particle diameter of 0.05 to 1 μm are subjected to surface treatment with a condensed phosphoric acid and an organic modified silicone oil; and a resin, wherein a content ratio between the white pigment and the surface-treated calcium carbonate is, in mass ratio (white pigment to surface-treated calcium carbonate), within a range of 90:10 to 60:40, and a total content of the white pigment and the surface-treated calcium carbonate in the resin composition is within a range of 5 to 70% mass.