Provided is a partial drive-type light source device capable of suppressing coloring of a section intended to be a dark section when a plurality of light-emitting elements is driven in a partial manner. The partial drive-type light source device includes an excitation light source, a phosphor sheet that is disposed at a position separated from the excitation light source and contains a phosphor that releases emitted light in a wavelength region differing from incident light, and a wavelength-selective reflection film that is disposed between the excitation light source and the phosphor sheet and that transmits at least part of light in the wavelength region of the incident light from the excitation light source and reflects at least part of light in the wavelength region of the emitted light from the phosphor sheet.