Mathematic geometry teaching auxiliary round tape

The utility model discloses a mathematic geometry teaching auxiliary round tape. The mathematic geometry teaching auxiliary round tape comprises a rotating device and a positioning device, wherein the rotating device is provided with a slide groove fork plate, a rotating cylinder, a threaded groove, a compression groove, a through hole, a gland, a magnetic ring, a spring, a spring pressure plate, a cylindrical chalk and a separation plate; the positioning device is provided with a connecting square block, a lower supporting plate, a threaded hole, an upper pressure plate, a through hole, a tightening screw, a rotating hole, a rotating rod, a hand pressure plate, a limiting plate, a rolling ball, a rotating groove and a positioning plate. The mathematic geometry teaching auxiliary round tape is simple inn structure, a circle can be rapidly drawn in the teaching process by virtue of a scale straight plate, the diameter of the circle can be adjusted randomly, the chalk can be automatically fed by virtue of the restoration force of a spring and the magnetic attraction effect on the front end; moreover, the round tape also can be used as a ruler, so that convenience can be brought to the teaching process.