A tantalum sintered body comprising a pore size distribution having a plurality of peaks wherein out of a plurality of peaks, two peaks having a largest relative intensity and a second largest relative intensity have a pore diameter of 0.2 to 0.7 μm and a pore diameter of 0.7 to 3 μm, having a volume of pore 10 mm3 or more including the volume of pore voids and a specific area of 0.2 to 7 m2/g, and having a CV value of 40,000 to 200,000 μFV/g when sintered at 1,300° C., and a capacitor using the sintered body.