To provide an excavation tool having a brazed join part of a cutting edge piece having excellent resistance against impact and join strength.

In this excavation tool having a structure constituted by fixing a plurality of posts made of tungsten carbide base cemented carbide according to a predetermined arrangement on a tip face of a bit main body made of alloy steel and brazing the cutting edge pieces made of sintered diamond directly on respective tip side faces of the posts, an extra-high pressure and temperature reaction generation metallic carbide layer made of either of carbide of Ti, Zr, Ta, Nb, and Mo and composite carbide made of two kinds or more of them is formed over an average depth of 0.01 to 0.5 mm from a surface, and the cutting edge piece forming the extra-high pressure and temperature reaction generation metallic carbide layer is brazed on a brazing join face on the post using an Ag alloy brazing material containing mass % of 20 to 40% of Pd, 15 to 25% of Cu, and 2 to 8% of Ti and having a composition in which the remaining parts are composed of Ag and unavoidable impurities.