The invention is related to the systems of so-called "security entrance" and, in particular, to the systems for preventing the entry of forbidden articles and/or substances from an unprotected area to a protected one. The simplicity, efficiency and secrecy of examination in a security system for preventing the entry of forbidden articles and/or substances from a surrounding area to a protected one, said system comprised of a partitioning separating a protected area from an unprotected one, at least, one walk-gate made in said partitioning, an information control-and-processing device and a detector of forbidden articles and/or substances is achieved due to said detector of forbidden articles and/or substances made an X-ray kind to provide secret examination of every person passing through said walk-gate.