provided are : a light source device capable of preventing light from a light source disposed to face an end surface of a light guide plate from leaking to a side in which the light guide plate emits the light without providing a new member ; and a display apparatus including the light source device . a light source unit 2 is disposed to face an end surface of a light guide plate 3 , and a heat spreader supporting the light source unit 2 has a shape of covering the light source unit 2 . a light from the light source unit 2 is irradiated to the end surface of the light guide plate 3 , as well as the protrusive plates 71 and 72 side of the heat spreader . since the light irradiated to the protrusive plate 71 side is shielded by the protrusive plate 71 , the light does not leak to a panel chassis 5 side .