Provided is an X-ray photographing apparatus including an X-ray source for generating and irradiating an X-ray； a collimator for controlling an X-ray photographing area to which an X-ray is irradiated by the X-ray source； a projector for generating and projecting a visible ray image by using image signals； a reflection mirror for reflecting the visible ray image projected by the projector to an X-ray photographing area； and a main controller for controlling the projector to match a light irradiation field corresponding to the visible ray image projected to the X-ray photographing area to the X-ray irradiation field.
