Disclosed is a cutting tool assembly employing a composite hard sintered body as a cutting part comprising a support and a cutting edge; wherein the cutting part is secured on a base made of a cemented carbide or a hard alloy having at least one edge where a recess is formed, the cutting part being formed by bonding a hard sintered body constituting the cutting edge and a cemented carbide or a cermet consituting the support, and said cutting part being secured in the recess by soldering in such a way that the support side may face the recess.
