PURPOSE: To facilitate the use of a protractor, and to achieve the convenience of use thereof by applying transmission cutoff to the protractor, and by describing the figures of 0 to 180 degrees on one side and the figures of 180 to 360 degrees on the other side between the angular graduations.

CONSTITUTION: The graduations of angles and the figures representing the angles are described on both sides of a transmission cutoff material of a plastic layer in the portion corresponding to the angular graduations and their figures of a protractor. In other words, on the rear side 1 of the protractor, the figures 3 of angles from 180deg. to 360deg. are described at the interval of 10deg. between the angluar graduations 4, and on the front side transmission cutoff surface of the protractor layer, the figures 3 of angles from 0deg. to 180deg. are described at the interval of 10deg. between the angluar graduations 4.