An anti-intrusion lock includes a sliding element at a handle shaft, a stop element under the handle shaft, wherein the stop element is suitable for moving upward or downward, a clamp button and a sliding lever connected to the clamp button, wherein the clamp button is led to be exposed and protruded from a side of the lock. When the lock is locked, the clamp button is pressed down to drive the sliding lever to push the stop element upward such that the stop element is stopped at the handle shaft. Thereby, when a thief turns the handle shaft, only the sliding element is driven to move along a sliding groove set at the lock such that the lock pretends to open and the thief misunderstands the lock has been broken and gives up intruding.