1. An X-ray imaging detector for generating X-ray transmitted image in a form of electric signal, for use in X-ray imaging apparatus which comprises the X-ray imaging detector, an X-ray generator, and a fixing means for fixedly positioning an object to be examined between the X-ray generator and the X-ray imaging detector mounted thereon, whereby X-ray imaging is performed by moving the X-ray generator and the X-ray imaging detector both interposing the object fixedly positioned by the fixing means while keeping facing each other, an imaging element for generating electric charged image constituting X-ray transmitted image by detecting X-ray radiated from said X-ray generator and transmitted through said object, a TDI (Time Delay Integration) clock generator for generating TDI clock signal, and a TDI clock controller for controlling generating of TDI clock signal from said TDI clock generator based on TDI frequency control data for controlling the frequency of the TDI clock signal and for executing TDI control of the electric charged image generated by said imaging element corresponding to said TDI clock signal.