Disclosed is a separator for an electrochemical device. The separator has an electrode adhesive layer, and two types of solvents are used when coating the electrode adhesive layer, wherein the ratio of polarity of the solvents is used to induce a beta crystal phase of the second binder resin, and thus a uniform porous structure is formed to provide an improved lithium-ion conduction path. In this manner, even when the adhesive layer is formed on the separator, the separator does not cause an increase in resistance.