Light having entered a light transmitting member through a predetermined point on an optical axis undergoes internal reflection in a front surface perpendicular to the optical axis, then undergoes internal reflection again in a rear surface composed of a paraboloid of revolution having a focal point at a position of plane symmetry with the predetermined point, and then exits the front surface. A mirror-finished annular region around the optical axis in the front surface has an outer peripheral edge set to be near a position where the incident angle of the light emitted from the light emitting element is equal to a critical angle, and an inner peripheral edge near a position where the light having undergone internal reflection in the front surface enters a position immediately behind the outer peripheral edge in the rear surface.