An X-ray CT apparatus having X-ray irradiator for irradiating an X-ray to an object to be inspected, an X-ray sensor for detecting an X-ray passed through the object to be inspected, an X-ray sensor signal processing circuit for processing an output signal from the X-ray sensor, and a CT control apparatus for reconstructing an image of the object to be inspected on the basis of an output signal of the X-ray sensor processed by the X-ray sensor signal processing circuit. The X-ray sensor signal processing circuit removes a DC component from the output signal of the X-ray sensor and integrates the output signal of the X-ray sensor having the DC component removed therefrom.