The present invention relates to the protractor a bar self-laying, the subject innovation is manufactured onto a semi-circular, base line, the horizontal line and plotted center point, in the protractor is the angular scale drawn representing the angle along the circumference, the center point of the protractor There doedoe self-tightening bar which rotates in combination with the rivet, is the scale indicating the length in characters the bar univariate drawn, tabyeon is characterized in that having been rotated so that coincides with the horizontal line. Further, at both sides of said bar characterized in that the fastening bolt, a height adjustment for compensating for the height difference by the height of the protractor. Thus, the rod self-laying protractor according to the present invention is a chair with a protractor that when improving the operability by being provided integrally and, there is an effect that it is possible to prevent the loss, drawn to an indication of the exact angle by those bar it is able to have an effect that can be drawn without errors.