Brake disc thickness measuring tool

The utility model relates to a brake disc thickness measuring tool, which can conveniently and quickly measure the thickness of a brake disc of an automobile without dismounting a tire. The brake disc thickness measuring tool comprises: a main scale, one end of which in the length direction is provided with a holding part, and the other end of which in the length direction is provided with a first clamping part; a slide bar capable of sliding in the longitudinal direction along a slide groove formed in the main scale, the slide bar having a second locking portion formed at one end thereof extending in the longitudinal direction relative to the first locking portion; the digital display module is fixed at the other end of the sliding rod and can measure and display the relative sliding distance between the main ruler and the sliding rod, the first clamping part is provided with a first protruding part protruding towards one side of the width direction of the main ruler, and the second clamping part is provided