Provided are a radiation sensor having a first flexible substrate provided with a phosphor layer which converts incident radiation into an electromagnetic wave in a wavelength region that is at least different from that of the radiation; an organic photoelectric conversion layer which includes a charge transport layer and a charge generation layer containing a charge transporting agent and 55% by mass to 75% by mass of a polymer binder, and photoelectrically converts the electromagnetic wave; a second flexible substrate provided with a charge detection layer which includes a storage capacitor and a thin film transistor and is adapted to read electrical charge generated at the organic photoelectric conversion layer; and a polymer subbing layer disposed between the organic photoelectric conversion layer and the charge detection layer, and a radiation image detection apparatus using the radiation sensor.