1. A radiation imaging method using a radiation detector having a plurality of pixel groups, comprising: a first map producing step for producing a first defect map in which the position of a defective pixel group not functioning as a pixel is registered from the pixel group; a second map producing step for producing a second defect map in which the position of a pseudodefective pixel group of which only the function of a part need be corrected is registered; and a combined defect map producing step for producing a combined defect map in which a pixel group for effecting defect correction is registered on the basis of the first defect map and the second defect map.