An diagnostic X-ray radiography device and system whereby a subject (M) can be placed on and taken off of an imaging bed safely, easily, and comfortably. In the device and system a placement-accommodating-state memory (21) stores a plurality of placement-accommodating states each consisting of an imaging bed (1) position and orientation and an X-ray tube (4) position that accommodate a given placement state of the subject (M). A placement-accommodating-state control unit (22) is provided that, if a desired placement-accommodating state is specified from among the plurality of placement-accommodating states by means of a control panel (11), makes the position of the imaging bed (1) and the position of the X-ray tube (4) conform to the specified placement-accommodating state. A placement-accommodating state is thus set automatically, so that the subject (M) can be placed and removed from the imaging bed (1) easily without a collimator (4a) attached to the X-ray tube (4) getting in the way.
