Provided is a radiation detector 1 capable of improving reliability associated with radiation detection. The radiation detector 1 includes: a supporting substrate 2 that can transmit radiation there-through a scintillator layer 3 formed on one principal surface 2a of the supporting substrate 2, the scintillator layer 3 including an incident surface 3a on which radiation is incident and an emission surface 3b emitting light generated by the incident radiation and on a side opposite to the incident surface 3a and a light detection portion 5 disposed on an emission surface side of the scintillator layer 3 for detecting light emitted from the emission surface 3b.
