The present invention locates a plurality of guides of the ruler in parallel in a multistage fashion, and finds the corresponding guide lines having the same length as the depth of the lesion when the length of the pile is reset to the same length as the depth of the lesion initially measured after the decay treatment. It is related with the ruler for measuring the length of the wound of the dental neurotherapy pile, which can be set quickly and accurately by simply fitting the end to the stopper (A-2) against the measurement surface. The configuration thereof includes a plate 10 having an external measuring surface 10-1 at one end thereof so that the stopper A-2 fitted into the neurotherapy file A is in close contact； Insert the neurotherapy file (A) into the wound hole (H) of the tooth (T) plate (so that the measured depth from the end of the bottom to the stopper (A-2) in close contact with the upper part of the tooth (T) ( A plurality of points are displayed in parallel on the plate 10 in a direction perpendicular to the external measuring surface 10-1 of Fig. 10, and points of the corresponding length from the external measuring surface 10-1 on each path of the portions marked in parallel. A guide line 11 on which a leader line 11-1 indicating up to 11 is displayed； A notification unit 12 displayed near the leader line 11-1 of each guide line 11 and indicating the length from the external measurement surface 10-1 to the corresponding leader line 11-1 in numbers or letters； And a wearing member 13 integrally mounted on the bottom of the plate 10 and spreading and pinching the open both ends so as to be worn and removed from the finger.본 발명은 룰러의 안내선 복수 개를 병렬로 다단식 형태로 배치하여, 충치 치료 후 초기에 측정한 환부 깊이와 동일한 길이로 파일의 길이를 다시 설정할 때 파일 끝단부를 환부 깊이와 동일한 길이를 갖는 해당 안내선 찾아 그 단부에 간단히 일치시킨 후 스토퍼(A-2)를 측정면에 밀착시킴으로써 신속하면서도 정확하게 파일 길이를 설정할 수 있도록 하는 치과 신경치료 파일의 환부길이 측정용 룰러에 관한 것으로,이의 구성은 신경치료 파일(A)에 끼워진 스토퍼(A-2)가 밀착되도록 일단에 외부측정면(10-1)을 갖는 플레이트(10)； 신경치료 파일(A)을 치아(T)의 환부 구멍(H)에 삽입하여 그
