Provided are a filter capable of detecting light with less noise, an optical sensor, a solid-state imaging element, and an image display device. This filter is provided with a plurality of different pixels that are two-dimensionally arranged, and at least one of the plurality of pixels is a pixel 11 of a near-infrared cut filter that shields at least a part of light having a wavelength in the near-infrared region and transmits light having a wavelength in the visible region.