A planar solar concentrator includes a light collecting assembly and a light condensing unit. The light collecting assembly includes a light collecting unit and a waveguide slab extending in a longitudinal direction. The light collecting unit includes a light collector having an input surface, an output surface, and a curved surface to direct an incident light toward a collecting zone on the output surface. The light condensing unit is slidably coupled to a rear end of the waveguide slab for condensing the incident light from the waveguide slab, and is coupled such that based on an elevation angle of the light source, the light condensing unit is permitted to be driven to slide in a transverse direction.