A casing integrally includes a first accommodation part in which an optical part is accommodated and a second accommodation part in which an optical support is accommodated. Since the optical part which is a part of an optical plate member formed in a bent plate shape is supported by the optical support which is another part of the optical plate member, it is unnecessary to prepare a thick and robust member for supporting the optical part. That is, the first accommodation part side of a light source device can be made thinner. Moreover, the second accommodation part side of a display apparatus functions as a stand for stationary installation of the first accommodation part side of the light source device. It is therefore possible to reduce the size of the light source device and also the display apparatus, since it is not necessary to attach a separate stand to the first accommodation part side of the light source device.