PROBLEM TO BE SOLVED: To provide an X-ray CT apparatus capable of reconstructing volume data being accompanied by processing to reduce artifact due to an X-ray high absorbent without an operator performing any operation.SOLUTION: An X-ray CT apparatus 1 according to the present embodiment comprises: an X-ray detection unit 115 for detecting an X ray generated by an X-ray generating unit 105 a projection data generation unit 200 for generating projection data on the basis of the output from the X-ray detection unit 115 a projection image generation unit 300 for generating a projection image on the basis of the projection data a determination unit 400 for determining the presence or absence of an X-ray high absorbent which has an X-ray absorptivity higher than that of the tissue of a subject in the projection image, on the basis of the pixel values in the projection image and a reconstruction unit 500 which, when it is determined that the X-ray high absorbent is present in the projection image, activates an artifact reduction process for reducing the artifact due to the X-ray high absorbent and reconstructs the volume data of the subject being accompanied by the artifact reduction process based on the projection data.
