A variable-throat exhaust turbocharger has a variable throat mechanism that reduces wear of contact surfaces of connection pin parts formed integral with lever plates or a drive ring and the grooves into which the connection pin parts are engaged. A mechanism also prevents slipping out of the drive ring from a nozzle mount toward the lever plate to prevent a probable occurrence of failure in action of the variable throat mechanism caused by the slipping out of the drive ring. The connection pin parts connecting between the lever plates and drive ring of the variable throat mechanism are formed integral with either the lever plates or the drive ring by extrusion or by precision casting. At least the connection pin parts or grooves into each of which each of the connection pin parts, is engaged, are treated with surface hardening including diffusion coating.