When coherent light beams, i.e., laser beams, are incident on one end of an optical fiber and transmitted to another end to exit from there so as to form an output light spot on a screen, non-uniform intensity distribution called a speckle pattern is often recognized in the output light spot. The authors confirmed that when a multimode optical bare fiber is placed in a loop onto a support plate, the speckle pattern in the output light spot appears to rotate while rotating or tilting the support plate. When an optical fiber is placed in a U-shape, instead of a loop, onto the support plate, the similar rotation of speckle pattern can also be observed. It was further confirmed that a distance between the optical fiber placed in parallel at the edge of the support plate provides certain influences on the observed rotating characteristics of the speckle pattern. The pattern rotation seems to be caused by upward and downward displacements of the optical fiber at the edge of the support plate. In addition, even in the case where a jacket-covered and connector-attached optical fiber is placed in the U-shape on the support plate and a laser diode is employed as a light source, similar speckle pattern rotation can be recognized. Such rotation phenomena of speckle patterns are observed with relatively good reproducibility, and therefore, there is a possibility of employing these phenomena for sensing purpose.