To provide a portable solid-state radiation detector, i.e. a thin portable FPD (flat panel detector) compatible with a cassette for CR (computed radiography), wherein a scintillator is not destroyed even if a pressure is applied externally in a normal use state and occurrence of glare due to scattering of radiation can be prevented.

The portable solid-state radiation detector 1 having a housing 3 which houses a sensor panel 21 equipped with a plurality of photoelectric conversion means 152 formed on a substrate 213 and a scintillator 211 provided on the photoelectric conversion means 152 opposite thereto and converting incident radiation into light, and a base 24 provided with a circuit 23 related to the photoelectric conversion means 152 on the surface opposite to a surface facing the sensor panel 21, is further provided with a cushioning member 25 between the sensor panel 21 and the base 24.