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 the output signal of the X-ray
sensor processed by the X-ray sensor signal processing circuit. The X-ray sensor
signal processing circuit includes a filter for removing a DC component from the
output signal of the X-ray sensor and a circuit for obtaining a difference between
a voltage corresponding to a current including a dark current generated in the
X-ray sensor by incidence of the X-ray and a voltage corresponding to the dark current.
