Provided is a slot die for improving coating uniformity including a main body, a cavity formed in the main body, an introduction part formed at an upper portion of the main body to supply a coating solution into the cavity, an injection unit configured to provide an external ejection path for the coating solution with respect to a portion of or the entire cavity, and a guide member arranged in the cavity to help diffusion of the coating solution to the injection unit.Accordingly, the guide member arranged in the cavity can induce diffusion of the ejected coating solution so that the coating solution can be more uniformly applied.