To provide a radiographic apparatus capable of highly accurately determining a readout timing of an X-ray detection signal, while independently constituting an X ray generator from the readout device for reading the X-ray detection signal.

With the operation of an X-ray tube 2 constituting the X-ray generator A, the rotation speed of a positive electrode rotating on the inside is monitored by a detector 6 disposed outside the X-ray tube 2, an actual measurement value detected by the detector 6 and a predetermined reference value are compared by an FPD control section 7, and the X-ray detection signal is read from the FPD 3 from a time when the actual measurement value falls below the reference value.