Photodetector, solid-state imaging element, and method for manufacturing photodetector

A photodetector (10) is provided with: a semiconductor substrate (100); a photoelectric conversion unit (101) provided on the semiconductor substrate (100); and a light-condensing unit (300) which faces the photoelectric conversion unit (101) and has light transmissivity. The light-collecting section (300) has an inorganic material layer (301) and an inorganic material layer (302) having a refractive index lower than that of the inorganic material layer (301), the inorganic material layer (301) is disposed such that at least a portion thereof overlaps the photoelectric conversion section (101) in plan view, and the inorganic material layer (302) is disposed so as to cover the inorganic material layer (301). 光检测器(10)具备半导体基板(100)、光电转换部(101)，被设置在半导体基板(100)；以及聚光部(300)，与光电转换部(101)相对，且具有透光性。聚光部(300)具有无机材料层(301)和折射率比无机材料层(301)的折射率低的无机材料层(302)，在平面图中无机材料层(301)被配置为至少一部分与光电转换部(101)重叠，无机材料层(302)被配置为覆盖无机材料层(301)。