Provided is a method for fabricating a rim type photomask. The method includes forming a light blocking pattern and a phase shift pattern on a substrate, forming a groove in the substrate by etching an exposed portion of the substrate using the light blocking pattern and the phase shift pattern as an etch mask, forming a mask layer filling the groove formed in the substrate, forming a mask pattern selectively exposing the groove formed in the substrate by patterning the mask layer, reducing a critical dimension (CD) of the mask pattern by irradiating ultraviolet (UV) rays onto the substrate, etching the light blocking pattern using the mask pattern having the reduced CD as an etch mask; forming a height difference by etching the phase shift pattern by a predetermined thickness from a top surface of the phase shift pattern that is exposed by the etching of the light blocking pattern; and forming a photomask including a rim region defined by the phase shift pattern having the height difference by removing the mask pattern.