An optical sensing device adopted to use structured light to detect an object is provided. The optical sensing device includes a structured light projector and a sensor. The structured light projector includes a light source and at least one beam multiplication film. The light source is configured to emit a light beam. The at least one beam multiplication film is disposed on a transmission path of the light beam and is made of anisotropic refractive index material, wherein a plurality of separated light beams are produced after the light beam from the light source passes through the at least one beam multiplication film, so as to form the structured light. The sensor is configured to sense the structured light reflected from the object. Besides, a structured light projector is also provided.