PROBLEM TO BE SOLVED: To deal with dirt caused by a body fluid or the like to avoid affecting the adjustment of a position of a cassette.SOLUTION: A cassette 13 comprises: a detection panel 16 for operating as radiation detection means a housing 26 for housing the detection panel 16 and the like and a sheet material 27 for being detachably attached to the housing 26. The housing 26 includes a front part 31 for covering the detection panel 16, a back face part 32, and a rectangular carbon plate 33 disposed in a position facing a detection range 16a of radiation in the detection panel 16 so as to cover the detection range 16a. The sheet material 27 is attached to a surface of the carbon plate 33 exposed from an opening 31a of the front part 31. A rectangular frame-shaped indicator 27a for indicating the detection range 16a and a cross-shaped indicator 27b for indicating the center of the detection range 16a are printed on the sheet material 27.
