Abstract: When daylighting into a building interior, this daylighting structure attenuates the brightness of a setting sun or a winter-time incoming light of small elevation angles, and causes the incoming light to be diffusely emitted toward the ceiling surface or into a deep portion of the indoor space domain regardless of the elevation angle thereof. An incoming light (E20) of 20° in elevation angle is caused to be diffusely emitted toward the ceiling surface on the internal upper side of the building through the refraction and reflection actions mediated by a light-transmitting material mounted in a horizontal direction opening of a wall.