A solid-state radiation detector is provided which has an improved positional precision within a casing thereof while ensuring the shock resistance properties. A radiation cassette comprises: a solid-state radiation detector which is an image pickup device, a casing constituted by upper and lower shell halves and accommodates therein the solid-state radiation detector and the like. Each of the upper and lower shell halves comprises: an outer frame; an inner frame, and a coupling member for coupling the outer and inner frames. A space between the outer frame and the inner frame is filled with a shock absorbing material, thereby imparting shock absorbency to the casing itself. The solid-state radiation detector is rigidly secured to the inner frame of the lower shell half.