In the X-ray CT apparatus of the present invention, the setting device sets X-ray irradiation condition candidate by at least one combination of a tube current and tube voltage for power to be supplied to the X-ray source by the use of an X-ray absorption coefficient of said scanning subject site of the object, and the control device makes the display device selectably display each of the set X-ray irradiation condition candidates which is provided for a diagnosis of a requested tissue of the object, to take control such that a tomographic image of the object is taken according to the selected X-ray irradiation condition candidate. According to the X-ray CT apparatus of the present invention, it is possible to set a scanning condition in view of absorption or transmission of X-rays specific to and different among each tissue of an object.