Planar light source device and liquid crystal display using the same

To provide a planar light source device capable of preventing abnormal light emittance at a vicinity of a lamp without causing deterioration in brightness and disadvantage in view of structure and a liquid crystal display having high display grade, by projecting a reflection sheet 4 from a light guiding plate 3 to inside of a lamp reflector 2 and providing notch portions 5 at both end portions of the reflection sheet 4 projected to inside of the lamp reflector 2 , interference between the projected reflection sheet 4 and electrode portions or lamp holders 1 a at both ends of the lamp 1 is prevented from causing.