A radiation imaging apparatus comprising: a first and second radiation-generating units adapted to irradiate the object with first and second radiation from a first and second directions a first radiation-detection unit adapted to detect the first radiation irradiated by the first radiation-generating unit and transmitted through the object a second radiation-detection unit adapted to detect the second radiation irradiated by the second radiation-generating unit and transmitted through the object and the first radiation irradiated by the first radiation-generating unit and scattered by the object a readout unit adapted to read out image information indicating a result of imaging of the object from the second radiation-detection unit an image-analysis unit adapted to analyze the image information read out by the readout unit and a radiation-control unit adapted to control an irradiation timing of the second radiation by the second radiation-generating unit based ON an analysis result obtained by the image-analysis unit.
