Synsphyronus niger 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 male is 3.6 mm. The colour is mainly brown.
The species occurs in south-eastern Australia in woodland habitats. The type locality is Adelaide.
The pseudoscorpions are terrestrial predators.