PURPOSE: To transform a luminous flux into plural static light beams, by making the luminous flux moving relatively along a concentric circle of the optical axis of a discoidal Fresnel lens incident on the Fresnel lens which has different focal points to incident light beams made incident on different radial positions of the lens.

CONSTITUTION: Incident light beams coming through optical fibers 23, 24, and 25 are made incident on different radial position of a Fresnel lens 32 after they are transformed into parallel light beams by a collimator 27. After forming their images at different focal points in accordance with their incident positions, the incident light beams to the Fresnel lens 32 are transformed into parallel light beams by means of collimators 31 installed to the focal points and led to optical fibers 33, 34 and 35. Therefore, plural pulsing or rotating light beams can be transformed into static light beams.