1. A radiographic image detection apparatus comprising: a radiation source that outputs radiation to a subject; a radiographic image detector that detects, as a radiographic image, the radiation that has been output from the radiation source and transmitted through the subject; a detector movement means that moves the radiographic image detector parallel to a radiation detection surface of the radiographic image detector; a yawing table that stores an inclination angle of the radiographic image detector at each position within a movement range of the radiographic image detector by the detector movement means; an image correction means that corrects, based on the position of the radiographic image detector when each of a plurality of radiographic images is obtained by the radiographic image detector moved to different positions from each other, inclination of the plurality of radiographic images respectively by using the yawing table; and an image synthesis means that produces a synthesis image by combining the plurality of radiographic images corrected by the image correction means.