An external tire pressure gauge mounting structure includes a base and a cap; the base and cap are locked together to provide an internal mounting space; the mounting structure also includes a gear, a cushion ring and a locking member; the gear is fixed on the base and has teeth; a through hole is defined in the cushion ring and teeth is provided on a sidewall of the through hole; the gear is inserted into the cushion ring, and the teeth of the cushion ring and gear mesh each other; the locking member is pressed against the cushion ring and gear; the locking member, gear and base all have their threaded holes. Also disclosed is a handling tool used for above mounting structure. The invention makes improvements upon the mounting structure of the tire pressure gauge and provides a handling tool which is easy to use. As such, mounting and dismounting of the tire pressure gauge becomes convenient.