To provide a radiation detection instrument capable of automatically regulating incident radiation dose without the need of high speed driving while suppressing an attenuation in radiation before detection, and its manufacturing method.

A read-out TFT1 is formed on an insulation substrate 11. A semiconductor layer 19 of an MIS photoelectric transducer 2 and an n+ semiconductor layer 20 are formed on a second insulation layer 18 covering the TFT1 to fit a source/drain electrode 16 capable of functioning as a lower electrode, and a semiconductor layer 21 of a TFT sensor 3 is formed to fit an electrode 17 in plan view. The semiconductor layers 19 and 21 are made of the same layer. An upper electrode 22 of the MIS photoelectric transducer 2 is formed on the n+ semiconductor layer 20. Two ohmmic contact layers 23 are formed on the layer 21, and one source/drain electrode 24 is formed on each of the layers 23.