1. A radiographic apparatus for acquiring fluoroscopic images of an object under examination, comprising: a radiation source for emitting radiation; a radiation detecting device for detecting the radiation; a radiation grid placed to cover a radiation detecting plane of the radiation detecting device; a pattern storage device for storing a plurality of patterns of shadows of the radiation grid falling on the radiation detecting device; an image generating device for generating an original image showing the object under examination and the shadows of the radiation grid, based on detection signals outputted from the radiation detecting device; a grid shadow estimating device for estimating a pattern of superimposed grid shadows, which are the shadows of the radiation grid appearing on the original image, from the patterns of shadows stored in the pattern storage device; and a removing device for removing the shadows of the radiation grid from the original image based on the superimposed grid shadows estimated; wherein the grid shadow estimating device is arranged to estimate the superimposed grid shadows based on a positional relationship between the radiation source and the radiation detecting device occurring at a time of acquiring the original image.