The present invention relates to a low pass filter including a wave plate capable of modulating incident light serving as image information such that A-polarized light and B-polarized light orthogonal to the A-polarized light are at an equivalent light quantity level over a visible light region, i.e., a transmittance takes a value close to 50%. According to the low pass filter of the present invention, it is possible to appropriately reduce a moiré phenomenon generated by an image sensor constituting the optical low pass filter including the above-described wave plate, and suppress degradation of an image quality caused by light quantity deflection of a separated light beam, and the low pass filter of the present invention is therefore useful.