Provided is an information providing method for aligning an X-ray tube and a detector of a mobile X-ray apparatus, the information providing method including: obtaining first angle information which relates to the X-ray tube by using a first angle measurement sensor which is connected to the X-ray tube obtaining second angle information which relates to the detector by using a second angle measurement sensor which is connected to the detector and outputting rotation information for guiding a rotation direction and a rotation angle of the X-ray tube or a rotation direction and a rotation angle of the detector such that an angle between a first plane which is set with respect to the X-ray tube and a second plane which is set with respect to the detector is within a predetermined angle range, based on the first angle information and the second angle information.
