A convex lens has surfaces including a flat surface and a projecting surface, and an anti-reflection structure configured to cover the projecting surface are included. The anti-reflection structure includes a first anti-reflection structure on the first end side, which is one of two end points of the line segment located nearer to the orthogonal projection of the apex than to the center point thereof, and a second anti-reflection structure on a second end side, which is one of the two end points of the line segment located nearer to the center point than to the orthogonal projection of the apex. A light transmittance of the second anti-reflection structure is greater than a light transmittance of the first anti-reflection structure.