The spear thrower is a tool that uses leverage to achieve greater velocity for various forms of darts.
The spear thrower is found in various cultures throughout the world It always consists of a handle whose far end holds the butt of the spear.
The far end of the shaft is affixed to the bearing of spear thrower. The thrower grabs the handle of the spear thrower and uses it to throw the spear. The device allows for greater speed and accuracy than simply throwing alone. In hunting, it would have changed the spear from a device primarily used in defense or throwing very short distances to a real tool.
Flinging the handle forward increases the force added to the throw, thus increasing the speed of the dart.