The present invention is for a switchable 3-dimensional conversion device having a spacer stably formed at a predetermined height by imprinting, a manufacturing method thereof and a stereoscopic image display device using the same, the method includes: providing a first electrode on an inner surface of a first substrate; applying a resin material to the first electrode to a predetermined thickness; placing a mold structure which has a concave part formed with a predetermined depth thereon, on the resin material; stamping the resin material using the mold structure, in order to form a spacer pattern; dry etching the spacer pattern to form a spacer; forming a plurality of second electrodes, which are spaced from one another and have longitudinal axes in one direction, respectively, on a second substrate; and arranging the first and second substrates opposite to each other, bonding the same, and forming a liquid crystal layer between the first and second substrates.