Two purpose protractor

The utility model relates to a double-duty protractor which has the advantages of simple and novel structure, low cost and convenient and fast use. The utility model comprises a body (1) and an indicating needle (2), wherein a semi-circular ring (11) on the upper part of the body is integrated with a diameter bottom margin (12) of the lower part, and the value of a bidirectional angle (13) is marked on the semi-circular ring; the inner side surfaces of the semi-circular ring and the diameter bottom margin are respectively provided with a groove (14); a guide line (15) is printed on the diameter bottom margin, and one side of the diameter bottom margin is also provided with a semi-circle gap (16); the needle tip of the indicating needle is contained in the groove of the semi-circle ring, and the needle foot is contained in the groove of the diameter bottom margin and is riveted with the diameter bottom margin by a pin; an indication line (21) is printed on the middle of the indicating needle, and a handle (22) is arranged on the indicating needle; the guide line on the diameter bottom margin intersects with the indication line of the indicating needle at the center of the circle; the indicating needle is just completely contained in the groove of the diameter bottom margin when the hand is moved to the semi-circle gap.