Synsphyronus magnus is a species of pseudoscorpion in the Garypidae family. It is endemic to Australia. It was described in 1947 by American arachnologist Clarence Clayton Hoff.
The body length of the holotype female is 4.45 mm. The colour is mainly brown.
The species occurs in south-west Western Australia in woodland habitats. The type locality is Margaret River.
The pseudoscorpions are terrestrial predators.