Tool holder with enhanced cooling effect

A tool holder, comprising:

• a body having
• a tool connecting portion having
• two opposite ends respectively being a front end and a rear end;
• a coolant entering groove;
• a connecting groove coaxially formed at a center of the tool connecting portion and having an opening near the front end;
• an annular ditch formed on an inside wall of the connecting groove and near the opening;
• and
• an annular inclined surface connected to a side of the annular ditch which faces the opening;
• and
• an included angle defined between the annular inclined surface and an axis of the body such that the annular inclined surface tapers away from the opening;
• and
• multiple flow passage systems formed on the body at spaced intervals, and each one of the multiple flow passage systems having
• an inlet passage disposed on the tool connecting portion and communicating with the coolant entering groove;
• a main passage extending from the inlet passage and through the front end of the tool connecting portion;
• and
• a branch passage extending obliquely from the main passage to the annular ditch and communicating with the annular ditch.