Disclosed apparatus comprises: a radiation detection panel in a housing, for detecting incident radiation as an electrical signal related to a radiation image; a support base in the housing and located on a side opposite to a radiation incident surface, for supporting the radiation detection panel from a back surface side; an internal structure in the housing and disposed on the back side surface of the support base; and fixing members in the housing, for fixing the internal structure to the support base, the difference in the radiation shielding efficiency between at least one of the fixing members and the support base is less than 50%, and when viewed from a radiation incident direction, a sheet like member having a radiation shielding efficiency of 50% or more is not arranged on a region on the back surface side of the radiation detection panel overlapping with the fixing member.