An image processing apparatus of the present invention performs reconstruction processing on a projected image of an object obtained by using a radiation source and a detector in order to obtain a tomographic image in which noise has been reduced regardless of the type of reconstruction filter that is used. The image processing apparatus includes a selection means that selects a reconstruction filter in accordance with an imaging technique； a setting means that sets an image processing parameter for noise reduction according to the type of the selected reconstruction filter； an image processing means that performs image processing on the projected image using the image processing parameter； and a reconstruction means that uses the selected reconstruction filter to perform reconstruction processing on the projected image resulting from the image processing and obtain a tomographic image of the object.
