A low-energy X-ray image formation apparatus includes an X-ray generator generating X-rays having an energy spectrum showing an energy range continuously ranging from 18-30 keV (or −37 keV), the energy range being higher in energy from an effective energy of an energy range ranging 10 to 23 keV. A detector detects the X-rays transmitted through a soft tissue of a subject or a tissue of a substance. The tissue of the substance corresponds in a contrast-to-noise ratio (CNR) to the soft tissue of the object. A console acquires an image of the soft tissue of the object or of the substance, based on a detection signal from the detector. The soft tissue and the substance are defined as a soft tissue and a substance presenting a CNR of 3.8 or more when the X-rays are radiated in a condition where an X-ray tube voltage is set at 20 kV.
