A light source apparatus includes first and second light direction changing faces that extend in a longitudinal direction, a light guiding member having first and second light emitting faces that are formed to respectively face the first and second light direction changing faces and a light source that is arranged on one end face of the light guiding member. A first vertical plane extending in a longitudinal direction with respect to the first light direction changing face and a second vertical plane extending in a longitudinal direction with respect to the second light direction changing face intersect. A groove which extends in a longitudinal direction of the light guiding member is formed between the first and second light direction changing faces. A surface forming the groove may be parabolic in a cross section.