A phosphor substrate having at least one light emitting element mounted on one surface, includes an insulating substrate, at least one electrode pair disposed on one surface of the insulating substrate and bonded to the light emitting element, and a phosphor layer disposed on one surface of the insulating substrate, including a phosphor in which a light emission peak wavelength, in a case where light emitted by the element is used as excitation light, is in a visible light region, in which a bonded surface of the electrode pair facing an outer side in a thickness direction of the insulating substrate, the bonded surface being bonded to the light emitting element, is positioned further on the outer side in the thickness direction than a non-bonded surface other than the bonded surface, and at least a part of the phosphor layer is disposed around the bonded surface of the one surface.