A flexible ionizer uses soft X-ray and has a head unit generating soft X-ray whose wavelength is 1.2˜1.5 Å, a soft X-ray protect unit shielding the leak of the soft X-ray from the head unit, and a power control unit supplying a control signal and control voltage to the head unit. The head unit is positioned outside of the soft X-ray protect unit with the flexible ionizer further having a flexible tube protecting a high voltage cable that connects the head unit and power control unit from external impact or vibration and letting the user bend the head of the head unit at an arbitrary angle toward a charged body if necessary, a connecting device letting the ions generated at the window positioned inside of the body of the ionizer emit toward the charged body by connecting one end of the flexible tube and the head unit, and a connecting device connecting the other end of the flexible tube and the body of the ionizer. The high voltage power lines in the flexible tube are molded to prevent short circuits occurring at a near distance between the high voltage power lines and mutual induction voltages occurring. The short circuit and the mutual induction voltage are caused by the mutual influence of the high voltage lines.