A niobium hydride or niobium hydride alloy is ground at a temperature of −200 to 30° C. in the presence of a dispersion medium to obtain a niobium powder for capacitors, having a low oxygen content, the niobium powder for capacitors is granulated to obtain a niobium granulated product for capacitors, having an average particle size of 10 to 500 μm, the niobium powder or granulated powder for capacitors is sintered to obtain a sintered body, and a capacitor is fabricated by forming a dielectric material on the surface of the sintered body and providing another part electrode on the dielectric material, whereby a capacitor having good LC characteristics and less dispersed in the LC characteristics is obtained.