An imaging photodetection device (4) includes: a plurality of photodetectors (6) that are arrayed on a substrate (5) at least along a first direction; a transparent low refractive index layer (12) that is formed above the plurality of photodetectors; and a plurality of transparent high refractive index sections (13) that are embedded in the transparent low refractive index layer along the first direction. On a cross-section of the transparent high refractive index sections orthogonal to the substrate and along the first direction, central axes (14) of the transparent high refractive index sections are bent stepwise. Light that enters the transparent low refractive index layer and the transparent high refractive index section passes therethrough to be separated into 0th-order diffracted light, 1st-order diffracted light, and −1st-order diffracted light. Thereby, improvement in the efficiency of light utilization and pixel densification can be realized.