The utility model relates to the technical field of drilling tool angle difference measure tools for directional wells and horizontal wells in petroleum drilling, in particular to a portable angle difference measure gauge, which comprises a point light source, a light source fixture, a dial, a directional drilling tool sub, a non-magnetic drill collar and a drilling tool screw, the directional drilling tool sub, the non-magnetic drill collar and the drilling tool screw are firmly connected together sequentially from the top down, the light source fixture is firmly mounted on the directional drilling tool sub, the point light source which can downwardly emit a linear light beam is firmly mounted on the light source fixture, a dial fixture is firmly mounted on the drilling tool screw, and the dial, the upper end surface of which is provided with angle scales, is fixed on the upper part of the dial fixture. The structure of the portable angle difference measure gauge is reasonable and compact, the portable angle difference measure gauge is convenient to use, the light source fixture and the dial are firmly mounted on a drilling tool, the reading projected on the dial by the point light source is observed, so that measured data can be directly obtained, and the portable angle difference measure gauge is characterized by high measured value precision, high measurement speed, simplicity and high efficiency.