The radiation image pickup apparatus of this invention can obtain an accurate temperature characteristic of dark current noise, the dark current noise being caused by dark current flowing through an X-ray conversion layer, by obtaining dark image signals at varied times for accumulating in capacitors charge signals converted by an X-ray converting layer. Consequently, the noise due to the dark current can be removed with high accuracy by removing periodically acquired offset signals from X-ray detection signals acquired at a time of X-ray image pickup, and correcting variations of the dark current noise due to a difference in temperature between a time of offset signal acquisition and the time of X-ray image pickup, using the temperature characteristic of the dark current noise.