A wavelength conversion device includes: a substrate; and a phosphor layer on the substrate. The phosphor layer includes: a base material; and a first phosphor and a second phosphor each of which emits fluorescent light when excited by excitation light. Where chromaticity coordinates of the fluorescent light emitted by the first phosphor and chromaticity coordinates of the fluorescent light emitted by the second phosphor are (x1, y1) and (x2, y2), respectively, −0.02≤x1−x2≤0.02 and −0.02≤y1−y2≤0.02 are satisfied. A peak wavelength of an excitation spectrum of the first phosphor is different from a peak wavelength of an excitation spectrum of the second phosphor.