It is described a contact probe for a testing head for a testing apparatus of electronic devices, the probe comprising a probe body extended in a longitudinal direction between respective end portions adapted to contact respective contact pads, the second end being a contact tip adapted to abut onto a contact pad of the device under test, the body of each contact probe having a length of less than 5000 μm, and including at least one pass-through opening extending along its longitudinal dimension. Conveniently, the at least one pass-through opening is filled by a filling material, in order to define at least one first and one second lateral portions in the body, being parallel and joined to each other by a connecting central portion realized by the filling material at the pass-through opening, the connecting central portion made of the filling material acting as a strengthening element.