A radiographic apparatus comprising, a radiation source for emitting radiation, a radiation detecting device having a detecting surface for detecting radiation, an image generating device for generating images in accordance with detection data outputted from the radiation detecting device, a collimator for restricting spread of a radiation beam emitted from the radiation source, an opening-degree obtaining device for obtaining a degree of opening of the collimator and a display device for displaying a radiation-irradiation area on the image, the opening-degree obtaining device determining the radiation-irradiation area to be displayed on the image in accordance with a relationship between a width of the radiation beam contained in the image obtained in advance by two or more degrees of opening of the collimator through radiation irradiation and the degrees of opening of the collimator as well as the current degree of opening of the collimator.
