According to the present invention, disclosed is an X-ray radiation field limiting apparatus of an automatic control type, capable of automatically adjusting and maintaining a X-ray radiation field to a predetermined X-ray radiation field range in accordance with a distance between a focus of an X-ray generator and a subject. The X-ray radiation field limiting apparatus of the present invention comprises: a main body disposed in front of an X-ray generator for generating X-rays； an X-ray radiation field limiting unit； a driving unit； a light radiation field apparatus； a distance information acquiring apparatus； and a controller. The X-ray radiation field limiting unit is mounted on the main body to adjust an X-ray radiation field formed by an X-ray radiated by the X-ray generator in accordance with an opening area of a variable window to maintain the same at a predetermined X-ray radiation field range. The driving unit operates the X-ray radiation field limiting unit to adjust the X-ray radiation field. The light radiation field apparatus is mounted on the main body to form the light radiation field aligned with the X-ray radiation field through the variable window with respect to the subject disposed in front of the main body. The distance information acquiring apparatus is mounted on the main body to measure and acquire a distance between a focus of the X-ray generator and the subject. The controller controls an operation of the driving unit on the basis of the distance received from the distance information acquiring apparatus to adjust the X-ray radiation field and the light radiation field by an operation of the X-ray radiation field limiting unit.COPYRIGHT KIPO 2018본 발명은 X-선 발생기의 초점과 피사체 사이의 거리에 따라 X-선 조사야를 미리 설정되어 있는 X-선 조사야 크기로 자동으로 조절 및 유지할 수 있는 자동 제어식 X-선 조사야 제한 장치를 개시한다. 본 발명은 X-선을 발생하는 X-선 발생기의 앞쪽에 배치되어 있는 본체, X-선 조사야 제한 유닛, 구동 유닛, 광 조사야 장치, 거리 정보 획득 장치와 컨트롤러로 구성되어 있다. X-선 조사야 제한 유닛은 X-선 발생기로부터 조사되는 X-선에 의해 형성되는 X-선 조사야를 가변 윈도우의 개도면적에 따라 조절하여 미리 설정되어 있는
