A radiographing apparatus includes a radiation detection panel including an effective image-acquisition area configured to detect radiation and a casing configured to house the radiation detection panel. The casing includes an incidence surface on which the radiation is incident, a back surface opposite the incidence surface, and a side surface between the incidence surface and the back surface. On the side surface of the casing, a level-difference portion indicating a position based on the effective image-acquisition area and a protrusion protruding more outward than the level-difference portion are provided.
