A handle locking structure includes a handle having a pivot portion pivotally connected to a sliding box, a buckle portion for hooking on a cabinet and a handle shaft, and a positioning structure including a base connected to the handle shaft, a positioning device mounted in the base and an elastic member placed on the positioning device. When the handle is hooked on the cabinet, a peripheral limiter of a head member of the positioning device is disengaged from a position-limiting notch of the base to reset the elastic member, so that the positioning device is automatically locked to the sliding box, avoiding vibration of the handle and improving the locking stability of the handle.