In a light source device, a row of fibers is provided in which a plurality of optical fibers is arrayed in a single row in parallel fashion separately from each other. A light-direction controller is disposed on one side of the optical fibers, main fibers is disposed above and below the light-direction controller, and a main fiber is disposed at the other end of the row of fibers. Light sources are connected to each of the end portions of the main fibers. Three types of mirrors that mutually differ in direction are formed on the surface of the light-direction controller, light emitted from a main fiber enters the optical fibers by way of a first mirror, and light emitted from a main fiber enters the optical fibers by way of a second mirror.