The present invention relates to a Shigella strain, of which the surface exposure of a protective antigen existing on a cellular membrane is increased due to the destruction of a wzy gene of Shigella sp., and to a vaccine composition for treating or preventing shigellosis, containing the mutant Shigella strain as an active ingredient. The Shigella strain of the present invention has a cell wall with a reduced thickness since a gene encoding a protein necessary for polymerization of the O-saccharide antigen is deleted, and as a result, membrane antigens including protein antigens commonly existing in different Shigella spp. are more exposed to immune cells, and thus the Shigella strain can be favorably used as a vaccine composition for treating or preventing shigellosis, derived from various Shigella spp.