Abstract: The invention relates to a pressure relief device (1) for a housing (2) which is protected against explosions, in particular is compression-proof and has a wall connecting piece (3) which can be at least partially inserted into a housing opening (4) of a housing wall (6) by its insertion connecting piece section (5), which can be in particular detachably fixed from an inner side of the housing and rests from the outside on an opening edge (8) of the housing opening (4) in its inserted and fixed position with a radially outwardly projecting support flange (7), wherein the insertion connecting piece section (5) furthermore comprises a projecting connecting piece section (9) which is opposite the insertion connecting piece section relative to the support flange (7) and comprises a longitudinal conduit (10) running through the wall connecting piece (3) into which conduit a flame-blocking body (11) is replaceably inserted, wherein a pressure nut (13) which loads the flame blocking body (11) with pressure in its in