Partition member, planar light source, and liquid crystal display device

A planar light source is provided with: a plurality of light sources; a substrate; a first member including a plurality of recessed first partition portions arranged in the row-column direction and a recessed second partition portion adjacent to the first partition portions; and a second member disposed so as to overlap on a portion of the first member, the first partition portion including a first inclined portion and a first bottom portion continuous from a lower end of the first inclined portion, the second partition portion including a second inclined portion and a first opening portion reaching a lower end of the second inclined portion in a plan view, the second member including: a third inclined portion, the second inclined part overlaps with the second inclined part on the outer edge of the second component side. A fourth inclined part which is adjacent to the third inclined part and does not overlap with the second inclined part; a second bottom part which is continuously arranged in the first openin