A light source device and a projection type display apparatus include: an excitation light source; and a fluorescence light-emitting plate including a fluorescence light-emitting section arranged opposite to the excitation light source and a reflection section containing titanium oxide located on the opposite side of the excitation light source as viewed from the side of the fluorescence light-emitting section and arranged such as to be joined to the fluorescence light-emitting section. Then, excitation light from the excitation light source is projected onto the fluorescence light-emitting section so that fluorescence emission light is emitted from the fluorescence light-emitting section and reflected fluorescence light is emitted from the reflection section.