1. An image processing apparatus comprising: a storage unit configured to store first X-ray image data in which a blood vessel of an object is not visually enhanced, and second X-ray image data in which the blood vessel is visually enhanced; a specifying unit configured to specify a catheter image included in the first fluoroscopic image by performing image processing of the first X-ray image data; an extraction unit configured to extract a blood vessel region included in the second fluoroscopic image by performing image processing of the second X-ray image data; and a setting processing unit configured to set a region of interest based on the position of end point of the catheter.