To provide a compact medical X-ray imaging apparatus which is portable, with which it is possible to capture clear X-ray images while maintaining low radiation exposure, and with which it is possible to increase the life of X-ray sources. An X-ray imaging apparatus which is portable, and with which it is possible to capture clear X-ray images while maintaining low radiation exposure. This compact medical X-ray imaging apparatus comprises: a carbon nanostructure triode cold cathode X-ray tube that radiates X-rays; an X-ray image sensor that captures an image of X-rays that have passed through a patient; a first detector that detects the X-ray radiation dosage and that is positioned between the carbon nanostructure triode cold cathode X-ray tube and the X-ray image sensor, and within the range in which X-rays are irradiated rather than the X-ray effective imaging area irradiated by the X-ray image sensor; a second detector that detects the X-ray dose and is positioned in the center part of one side of the frame of the X-ray image sensor; a third detector that detects the X-ray dose and is positioned on one side of the frame of the X-ray image sensor sandwiching the detection surfaces of the X-ray image sensor and facing the second detector; a power supply which supplies a negative and a positive high-voltage pulse to the cathode and anode of the carbon nanostructure triode cold cathode X-ray tube respectively; and an X-ray imaging control device which acquires detection data from the first, second and third detectors in addition to information concerning the distance from the carbon nanostructure triode cold cathode X-ray tube to the X-ray image sensor, calculates the X-ray radiation dose and amount of decay, determines the optimum X-ray dose for the patient and the voltage of the carbon nanostructure triode cold cathode X-ray tube, and provided with feedback control that controls the pulse number and pulse width of the high-voltage pulse of the carbon nanostructure triode cold cathode X-ray tube, and the voltage of the cathode and the anode.