A high-speed tool holder includes: a tool shaft for accommodating a tool at its first end, and a machine clamping part which is integrally connected to the tool shaft and forms an interface for clamping in the machine; with the tool shaft being substantially truncated circular cone-shaped, a first diameter at the first end with the tool insertion opening being smaller than a fifth diameter at the second end at the machine clamping part; and a portion of the substantially truncated circular cone-shaped tool shaft having an outwardly bulging, preferably spherical, shape between the tool insertion opening and the machine clamping part.