1. A stereoscopic image display device, comprising: a stereoscopic display panel which includes: a light separating module which distributes a light ray at least into two different viewpoint directions; assuming that the direction of distributing the light ray as a first direction, a stereoscopic viewing space where a stereoscopic image is displayed by projecting a right-eye image to the right-eye of an observer and a left-eye image to the left eye of the observer, respectively; a pseudoscopic viewing space where the left-eye image is projected to the right eye and the right-eye image is projected to the left eye, respectively, which is at a position shifted from the stereoscopic viewing space in the first direction; and a 3D-crosstalk viewing space where the right-eye image and the left-eye image are projected to one of or both of the right eye and the left eye, which is between the stereoscopic viewing space and the pseudoscopic viewing space in the first direction; an observer position measuring unit which measures an observing position of the observer; a relative position calculating unit which calculates a relative position of the stereoscopic display panel with respect to the measured observing position; an image filter value calculating unit which calculates an image filter value for adjusting an amount of blur in an image according to the relative position; and an image blurring processing unit which performs image blurring processing on image data to blur the image according to the image filter value.