According to a radiographic apparatus of this invention, an image correcting unit corrects offset for every pixel relative to a detection value outputted from a radiation detector having pixels for detecting radiation arranged in a two-dimensional array. In addition, the image correcting unit corrects the offset while holding noise components contained in the detection value. Thus, upon quantitative evaluation of the noises contained in the detection values outputted from the radiation detector, the noises of not only positive values but also negative values can be considered. Consequently, accurate evaluation may be achieved.