An optical sensing device includes a substrate, a sensing element layer, a first planarization layer, and a second planarization layer. The sensing element layer is located on the substrate and includes a plurality of sensing elements. The first planarization layer is located on the sensing element layer and has a first slit. The second planarization layer is located on the first planarization layer and has a second slit. An orthogonal projection of the first slit extending in a direction and located on the substrate is not overlapped with an orthogonal projection of the second slit extending in the same direction and located on the substrate, and the orthogonal projection of the second slit on the substrate has a curved pattern.