Abstract: An optical fiber bundle structure includes: plural optical fiber core wires; a crossing preventing member; and a grasping member. Further, the crossing preventing member has slits and the widths of the slits positioned at the respective sides are each equal to or larger than a difference between: a length of one side of a polygon circumscribing the plural optical fiber core wires at a hindmost end portion of the slits at the trailing end; and a length of one side of a polygon circumscribing the plural optical fiber core wires at the leading end.

Abstract: An inclined surface-equipped lens includes a first inclined surface and a second inclined surface inclined relative to a plane perpendicular to an optical axis, and a corner portion formed by the first inclined surface and the second inclined surface being in contact with each other. Each inclined surface makes a predetermined inclination angle with the plane perpendicular to the optical axis, and the corner portion is located out of the optical axis and raised outward.

Abstract: An inclined surface-equipped lens includes a first inclined surface and a second inclined surface inclined relative to a plane perpendicular to an optical axis, and a corner portion formed by the first inclined surface and the second inclined surface being in contact with each other. Each inclined surface makes a predetermined inclination angle with the plane perpendicular to the optical axis, and the corner portion is located out of the optical axis and raised outward.