A daylighting film (1) according to an aspect of the invention includes a first base (2), a plurality of daylighting portions (3) constituted by a plurality of polygonal prism structures, and gaps (9) provided between the plurality of daylighting portions (3). Each of the daylighting portions (3) is a polygon that has four vertexes in a sectional shape orthogonal to a longitudinal direction and has all interior angles less than 180°, and has a first side that is a side of the polygon corresponding to a surface in contact with the first base (2) and a plurality of vertexes including a first vertex and a second vertex that are vertexes corresponding to both ends of the first side, and a third vertex that is not positioned on the first side. A length of a line perpendicular to the first side passing the third vertex is longer than lengths of lines perpendicular to the first side passing vertexes other than the third vertex among the plurality of vertexes, and a shape of the daylighting portion 3 is asymmetrical with the line perpendicular to the first side passing the third vertex as a center.