Abstract: A portable apparatus for cutting roofing shingles at various angles comprises a rigid frame assembly, a first cutting blade affixed to the frame assembly, a cutting blade assembly comprising a blade-supporting arm pivotally attached to the frame and a second cutting blade affixed to that arm and extending parallel to the first cutting blade, the cutting blade assembly being pivotable so as the second cutting blade can be pivoted into and out of a shingle-shearing relationship with the first cutting blade, and the blade-supporting arm being adjustable laterally of the first cutting blade so as to assure a clean shearing action. A movable guide fence assembly mounted on the frame accurately determines the angle at which a shingle is to be cut.