Radiation detector

A radiation detector comprising:

• a positioning member having a through hole through which radiation passes;
• a scintillator having an input surface to which the radiation passing through the through hole is input and configured to convert the radiation into scintillation light;
• a sensor unit having a light-receiving surface that receives the scintillation light converted by the scintillator and configured to detect the scintillation light;
• and
• a lens unit having a lens configured to perform image capturing on the input surface of the scintillator and the light-receiving surface of the sensor unit,
• wherein the positioning member has a first positioning portion with which at least a part of the input surface of the scintillator comes into contact to position the scintillator, and
• wherein the position member has a second positioning portion with which at least a part of one end face of the lens unit comes into contact to position the lens unit.