An object of the present invention is to provide an antimony-containing
niobium sintered body for a capacitor having a small specific leakage
current value, an antimony-containing niobium powder for use in the
sintered body, and a capacitor using the sintered body. In the present
invention, an antimony-containing niobium powder having an antimony
content of preferably about 0.1 to about 10 mol % and an average particle
size of preferably about 0.2 to about 5 .mu.m is used. By using this
antimony-containing niobium powder, a sintered body and a capacitor are
constructed.