A drywall corner bead cutting device includes a drywall corner bead retaining body having a cross-sectional shape approximately similar to the cross-sectional shape of the drywall corner bead to be cut, the retaining body including a longitudinally extended top wall plate and inner and outer base wall retaining elements for releasably retaining the drywall corner bead within the retaining body and at least one cutting blade assembly movably mounted on the retaining body which includes a handle and a cutting blade which extends through the retaining body to cut the drywall corner bead on a diagonal to permit the cut sections of drywall corner bead to be butted against one another to form a generally seamless joint.