1. A single-eye stereoscopic imaging device comprising: a single imaging optical system; pupil division unit for dividing beams passing through the imaging optical system into a plurality of beams; a single imaging element including a plurality of pixel groups which receive the plurality of beams; first shading correction unit for performing shading correction for all imaging signals output from the single imaging element using a two-dimensional correction table in which correction values for correcting shading in horizontal and vertical directions caused by at least the imaging optical system are arranged; and second shading correction unit for performing shading correction for each imaging signal output from the plurality of pixel groups using a one-dimensional correction table in which correction values for correcting shading in a gradient direction of density unevenness caused by pupil division of the pupil division unit are arranged.