In long-format radiography, a long-format imaging region is determined and the long-format imaging region is partitioned into a plurality of imaging regions. Following this, and prior to x-ray imaging, a particular location of an overlapping image area is illuminated by a laser line marker, through laser line marker emission controlling means, in order to confirm that no overlapping image area, which is provided in adjacent imaging regions when the long-format imaging region is partitioned, is positioned on a location of interest of the examination subject. The ability to indicate clearly the particular location of the overlapping image area, through the laser line marker, makes it possible to evaluate accurately whether or not an overlapping image area is positioned on a location of interest. Doing so makes it possible to set the imaging region easily.