Embodiments provide a light source module including a circuit board, at least two point light sources, which are electrically connected to the circuit board and are arranged on an upper surface of the circuit board in a longitudinal direction of the circuit board, and a light guide for guiding light, which is introduced from the point light sources, in an upward direction of the circuit board, wherein the light guide includes a first reflective wall, disposed on the upper surface of the circuit board, and a second reflective wall, disposed on the upper surface of the circuit board, such that a space, in which the point light sources are disposed, is defined between the first reflective wall and the second reflective wall. Embodiments also provide a planar light source device including the light source module.